diff --git a/app/api/bookkeeping/fiscal-periods/__tests__/route.test.ts b/app/api/bookkeeping/fiscal-periods/__tests__/route.test.ts
index 2bbd3949..6a3ec131 100644
--- a/app/api/bookkeeping/fiscal-periods/__tests__/route.test.ts
+++ b/app/api/bookkeeping/fiscal-periods/__tests__/route.test.ts
@@ -234,4 +234,114 @@ describe('POST /api/bookkeeping/fiscal-periods', () => {
     const res = await POST(req)
     expect(res.status).toBe(400)
   })
+
+  it('sets previous_period_id when chaining forward', async () => {
+    // Build a mock that captures the insert payload.
+    const insertSpy = vi.fn().mockReturnValue({
+      select: vi.fn().mockReturnValue({
+        single: vi.fn().mockResolvedValue({
+          data: { id: 'new-period', name: 'FY 2026' },
+          error: null,
+        }),
+      }),
+    })
+
+    let fpCallIndex = 0
+    const supabase = {
+      auth: { getUser: vi.fn().mockResolvedValue({ data: { user: { id: 'user-1' } } }) },
+      from: vi.fn().mockImplementation(() => {
+        fpCallIndex++
+        const callNum = fpCallIndex
+        return {
+          // eslint-disable-next-line @typescript-eslint/no-explicit-any
+          select: vi.fn().mockImplementation((_sel: string, opts?: any) => {
+            if (opts?.count === 'exact') {
+              return { eq: vi.fn().mockReturnValue({ eq: vi.fn().mockResolvedValue({ count: 0 }) }) }
+            }
+            if (callNum === 1) {
+              return {
+                eq: vi.fn().mockReturnValue({
+                  order: vi.fn().mockResolvedValue({
+                    data: [{ id: 'prior-period-id', period_start: '2025-01-01', period_end: '2025-12-31', is_closed: true, closing_entry_id: null }],
+                    error: null,
+                  }),
+                }),
+              }
+            }
+            return {
+              eq: vi.fn().mockReturnValue({
+                lte: vi.fn().mockReturnValue({
+                  gte: vi.fn().mockReturnValue({ limit: vi.fn().mockResolvedValue({ data: [], error: null }) }),
+                }),
+              }),
+            }
+          }),
+          insert: insertSpy,
+          update: vi.fn().mockReturnValue({ eq: vi.fn().mockReturnValue({ eq: vi.fn().mockResolvedValue({ error: null }) }) }),
+        }
+      }),
+    }
+    ;(createClient as ReturnType<typeof vi.fn>).mockResolvedValue(supabase)
+
+    const req = createMockRequest({ name: 'FY 2026', period_start: '2026-01-01', period_end: '2026-12-31' })
+    const res = await POST(req)
+
+    expect(res.status).toBe(200)
+    expect(insertSpy).toHaveBeenCalledTimes(1)
+    const insertArg = insertSpy.mock.calls[0][0]
+    expect(insertArg.previous_period_id).toBe('prior-period-id')
+    expect(insertArg.period_start).toBe('2026-01-01')
+  })
+
+  it('does not set previous_period_id for the first period', async () => {
+    const insertSpy = vi.fn().mockReturnValue({
+      select: vi.fn().mockReturnValue({
+        single: vi.fn().mockResolvedValue({
+          data: { id: 'new-period', name: 'FY 2025' },
+          error: null,
+        }),
+      }),
+    })
+
+    let fpCallIndex = 0
+    const supabase = {
+      auth: { getUser: vi.fn().mockResolvedValue({ data: { user: { id: 'user-1' } } }) },
+      from: vi.fn().mockImplementation(() => {
+        fpCallIndex++
+        const callNum = fpCallIndex
+        return {
+          // eslint-disable-next-line @typescript-eslint/no-explicit-any
+          select: vi.fn().mockImplementation((_sel: string, opts?: any) => {
+            if (opts?.count === 'exact') {
+              return { eq: vi.fn().mockReturnValue({ eq: vi.fn().mockResolvedValue({ count: 0 }) }) }
+            }
+            if (callNum === 1) {
+              return {
+                eq: vi.fn().mockReturnValue({
+                  order: vi.fn().mockResolvedValue({ data: [], error: null }),
+                }),
+              }
+            }
+            return {
+              eq: vi.fn().mockReturnValue({
+                lte: vi.fn().mockReturnValue({
+                  gte: vi.fn().mockReturnValue({ limit: vi.fn().mockResolvedValue({ data: [], error: null }) }),
+                }),
+              }),
+            }
+          }),
+          insert: insertSpy,
+          update: vi.fn().mockReturnValue({ eq: vi.fn().mockReturnValue({ eq: vi.fn().mockResolvedValue({ error: null }) }) }),
+        }
+      }),
+    }
+    ;(createClient as ReturnType<typeof vi.fn>).mockResolvedValue(supabase)
+
+    const req = createMockRequest({ name: 'FY 2025', period_start: '2025-01-01', period_end: '2025-12-31' })
+    const res = await POST(req)
+
+    expect(res.status).toBe(200)
+    expect(insertSpy).toHaveBeenCalledTimes(1)
+    expect(insertSpy.mock.calls[0][0].previous_period_id).toBeNull()
+  })
 })
diff --git a/app/api/bookkeeping/fiscal-periods/route.ts b/app/api/bookkeeping/fiscal-periods/route.ts
index 69425205..d31254f6 100644
--- a/app/api/bookkeeping/fiscal-periods/route.ts
+++ b/app/api/bookkeeping/fiscal-periods/route.ts
@@ -132,6 +132,19 @@ export async function POST(request: Request) {
     )
   }
 
+  // Resolve previous_period_id for forward chaining so the new period is
+  // linked to the period it follows. Without this, balance-sheet/trial-balance
+  // reports fall back to scanning every prior journal line (BFNAR 2013:2
+  // continuity chain is broken). Backward chaining sets previous_period_id
+  // on the old earliest period instead (see below), not on the new one.
+  let previousPeriodId: string | null = null
+  if (allPeriods && allPeriods.length > 0) {
+    const latest = allPeriods[allPeriods.length - 1]
+    if (body.period_start > latest.period_end) {
+      previousPeriodId = latest.id
+    }
+  }
+
   const { data, error } = await supabase
     .from('fiscal_periods')
     .insert({
@@ -140,6 +153,7 @@ export async function POST(request: Request) {
       name: body.name,
       period_start: body.period_start,
       period_end: body.period_end,
+      previous_period_id: previousPeriodId,
     })
     .select()
     .single()
diff --git a/components/import/ImportReviewStep.tsx b/components/import/ImportReviewStep.tsx
index 5feaf5e4..0870a381 100644
--- a/components/import/ImportReviewStep.tsx
+++ b/components/import/ImportReviewStep.tsx
@@ -82,7 +82,7 @@ export default function ImportReviewStep({
           .from('company_settings')
           .select('default_voucher_series')
           .eq('company_id', company.id)
-          .single(),
+          .maybeSingle(),
         supabase
           .from('voucher_sequences')
           .select('voucher_series')
@@ -91,8 +91,7 @@ export default function ImportReviewStep({
 
       if (cancelled) return
 
-      // PGRST116 = no rows returned from .single(); expected when settings not yet created.
-      if (settingsError && settingsError.code !== 'PGRST116') {
+      if (settingsError) {
         console.error('Failed to load company settings for voucher series', settingsError)
       }
       if (sequencesError) {
diff --git a/lib/import/__tests__/sie-import.test.ts b/lib/import/__tests__/sie-import.test.ts
index b73f0826..1bbc8c55 100644
--- a/lib/import/__tests__/sie-import.test.ts
+++ b/lib/import/__tests__/sie-import.test.ts
@@ -7,6 +7,7 @@ import {
   importVouchers,
   computeVoucherNumberRanges,
   linkOpeningBalanceEntryToPeriod,
+  companyHasPriorActivity,
 } from '../sie-import'
 import { createQueuedMockSupabase } from '@/tests/helpers'
 import type { ParsedSIEFile, AccountMapping } from '../types'
@@ -500,6 +501,104 @@ describe('linkOpeningBalanceEntryToPeriod', () => {
   })
 })
 
+describe('companyHasPriorActivity', () => {
+  // Guards multi-year SIE imports: when the company already has posted
+  // non-IB journal entries, creating another IB entry would double-count
+  // one year's movements against every balance-sheet account.
+  type Supabase = Parameters<typeof companyHasPriorActivity>[0]
+
+  function buildCountingSupabase(count: number) {
+    const capturedFilters: Record<string, unknown> = {}
+
+    const supabase = {
+      from: (table: string) => {
+        if (table !== 'journal_entries') {
+          throw new Error(`Unexpected table: ${table}`)
+        }
+        const chain = {
+          select: (_cols: string, opts?: { count?: string; head?: boolean }) => {
+            capturedFilters['_opts'] = opts
+            return chain
+          },
+          eq: (col: string, val: unknown) => {
+            capturedFilters[`eq:${col}`] = val
+            return chain
+          },
+          neq: (col: string, val: unknown) => {
+            const key = `neq:${col}`
+            const existing = capturedFilters[key]
+            if (Array.isArray(existing)) {
+              existing.push(val)
+            } else if (existing !== undefined) {
+              capturedFilters[key] = [existing, val]
+            } else {
+              capturedFilters[key] = val
+            }
+            return chain
+          },
+          in: (col: string, val: unknown) => {
+            capturedFilters[`in:${col}`] = val
+            return chain
+          },
+          then: (resolve: (v: { count: number; error: null }) => void) =>
+            resolve({ count, error: null }),
+        }
+        return chain
+      },
+    }
+    return { supabase, capturedFilters }
+  }
+
+  it('returns false when the company has no prior posted entries', async () => {
+    const { supabase } = buildCountingSupabase(0)
+
+    const result = await companyHasPriorActivity(supabase as unknown as Supabase, 'company-1')
+
+    expect(result).toBe(false)
+  })
+
+  it('returns true when the company has prior posted non-IB entries', async () => {
+    const { supabase } = buildCountingSupabase(42)
+
+    const result = await companyHasPriorActivity(supabase as unknown as Supabase, 'company-1')
+
+    expect(result).toBe(true)
+  })
+
+  it('excludes opening_balance and storno entries, and only counts posted', async () => {
+    const { supabase, capturedFilters } = buildCountingSupabase(0)
+
+    await companyHasPriorActivity(supabase as unknown as Supabase, 'company-1')
+
+    expect(capturedFilters['neq:source_type']).toEqual(['opening_balance', 'storno'])
+    expect(capturedFilters['eq:status']).toBe('posted')
+    expect(capturedFilters['eq:company_id']).toBe('company-1')
+  })
+
+  it('treats null/undefined count as zero', async () => {
+    const supabase = {
+      from: () => ({
+        select: () => ({
+          eq: () => ({
+            neq: () => ({
+              neq: () => ({
+                eq: () => ({
+                  then: (resolve: (v: { count: null; error: null }) => void) =>
+                    resolve({ count: null, error: null }),
+                }),
+              }),
+            }),
+          }),
+        }),
+      }),
+    }
+
+    const result = await companyHasPriorActivity(supabase as unknown as Supabase, 'company-1')
+
+    expect(result).toBe(false)
+  })
+})
+
 describe('isBalanceSheetAccount', () => {
   it('returns true for class 1 (assets)', () => {
     expect(isBalanceSheetAccount('1510')).toBe(true)
diff --git a/lib/import/sie-import.ts b/lib/import/sie-import.ts
index 487af160..b93956a9 100644
--- a/lib/import/sie-import.ts
+++ b/lib/import/sie-import.ts
@@ -459,6 +459,36 @@ async function createOpeningBalanceEntry(
   return entry.id
 }
 
+/**
+ * Returns true when the company already has at least one posted (or reversed)
+ * non-IB journal entry — i.e. this is a continuation import, not the first
+ * ever SIE upload for the company.
+ *
+ * Used to gate IB-entry creation: when a company is already live, each year's
+ * #IB equals the prior year's UB, which is the sum of already-imported
+ * journal lines. Creating a new IB entry would double-count one year's
+ * movements against every balance-sheet account.
+ */
+export async function companyHasPriorActivity(
+  supabase: SupabaseClient,
+  companyId: string
+): Promise<boolean> {
+  // Only count currently-effective real activity. Excluding 'reversed' drops
+  // cancelled originals; excluding source_type 'storno' drops their matching
+  // reversal entries so a fully-cancelled pair contributes nothing. Without
+  // this, repair scripts that storno duplicate IB entries would leave storno
+  // artifacts that trip the guard on a freshly-repaired company.
+  const { count } = await supabase
+    .from('journal_entries')
+    .select('id', { count: 'exact', head: true })
+    .eq('company_id', companyId)
+    .neq('source_type', 'opening_balance')
+    .neq('source_type', 'storno')
+    .eq('status', 'posted')
+
+  return (count ?? 0) > 0
+}
+
 /**
  * Link an opening-balance journal entry to its fiscal period so balance-sheet
  * reports use the explicit IB path in getOpeningBalances() (reads only that
@@ -1621,6 +1651,24 @@ export async function executeSIEImport(
       if (period?.opening_balances_set || period?.opening_balance_entry_id) {
         result.warnings.push('Ingående balanser finns redan för denna period — hoppar över IB-import')
       } else {
+        // Continuation-import guard: if the company already has any posted
+        // non-IB journal entries from a prior import or manual bookkeeping,
+        // do NOT create a new IB entry. Each year's #IB equals the prior
+        // year's UB, which is already the sum of the prior year's posted
+        // transactions — so importing another IB entry double-counts one
+        // year of activity against every balance-sheet account. The
+        // first-ever import creates the legitimate pre-system IB; subsequent
+        // imports must rely on the prior entries to derive opening balances
+        // on the fly (via getOpeningBalances() fallback).
+        const isContinuationImport = await companyHasPriorActivity(supabase, companyId)
+
+        if (isContinuationImport) {
+          result.warnings.push(
+            'Ingående balanser hoppades över eftersom bolaget redan har bokförda verifikationer. ' +
+            'Ingående balans för denna period härleds från föregående periods utgående balans. ' +
+            'Stäm av mot SIE-filens #IB om du är osäker.'
+          )
+        } else {
         const ibValidation = validateIBBalance(parsed, accountMap)
 
         if (ibValidation.lines.length > 0) {
@@ -1676,6 +1724,7 @@ export async function executeSIEImport(
             )
           }
         }
+        }
       }
     }
 
diff --git a/lib/reports/__tests__/continuity-check.test.ts b/lib/reports/__tests__/continuity-check.test.ts
index 7ebec826..125197f9 100644
--- a/lib/reports/__tests__/continuity-check.test.ts
+++ b/lib/reports/__tests__/continuity-check.test.ts
@@ -23,8 +23,14 @@ function makeBuilder(tableName: string) {
 }
 
 function makeClient() {
+  const rpc = vi.fn().mockImplementation(async (fn: string) => {
+    const queue = mockResults[`rpc:${fn}`]
+    if (!queue || queue.length === 0) return { data: [], error: null }
+    return queue.shift()!
+  })
   return {
     from: vi.fn().mockImplementation((table: string) => makeBuilder(table)),
+    rpc,
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   } as any
 }
@@ -66,9 +72,7 @@ describe('validateBalanceContinuity', () => {
         { data: { period_start: '2024-01-01', opening_balance_entry_id: null } },
       ],
       journal_entry_lines: [
-        // Previous period OB (fallback — no OB entry)
-        { data: [] },
-        // Previous period lines (trial balance)
+        // Previous period lines (trial balance — prior OB comes from RPC, defaults empty)
         {
           data: [
             { account_number: '1930', debit_amount: 50000, credit_amount: 0 },
@@ -113,7 +117,6 @@ describe('validateBalanceContinuity', () => {
         { data: { period_start: '2024-01-01', opening_balance_entry_id: null } },
       ],
       journal_entry_lines: [
-        { data: [] },
         // Previous UB: 1930 = 50000 debit
         {
           data: [
@@ -157,7 +160,6 @@ describe('validateBalanceContinuity', () => {
         { data: { period_start: '2024-01-01', opening_balance_entry_id: null } },
       ],
       journal_entry_lines: [
-        { data: [] },
         // Previous UB has 1510 and 2440
         {
           data: [
@@ -199,7 +201,6 @@ describe('validateBalanceContinuity', () => {
         { data: { period_start: '2024-01-01', opening_balance_entry_id: null } },
       ],
       journal_entry_lines: [
-        { data: [] },
         // Previous UB: only 1930
         {
           data: [
@@ -240,7 +241,6 @@ describe('validateBalanceContinuity', () => {
         { data: { period_start: '2024-01-01', opening_balance_entry_id: null } },
       ],
       journal_entry_lines: [
-        { data: [] },
         {
           data: [
             { account_number: '1930', debit_amount: 50000.005, credit_amount: 0 },
diff --git a/lib/reports/__tests__/general-ledger.test.ts b/lib/reports/__tests__/general-ledger.test.ts
index 525a7718..f789391c 100644
--- a/lib/reports/__tests__/general-ledger.test.ts
+++ b/lib/reports/__tests__/general-ledger.test.ts
@@ -23,8 +23,14 @@ function makeBuilder(tableName: string) {
 }
 
 function makeClient() {
+  const rpc = vi.fn().mockImplementation(async (fn: string) => {
+    const queue = mockResults[`rpc:${fn}`]
+    if (!queue || queue.length === 0) return { data: [], error: null }
+    return queue.shift()!
+  })
   return {
     from: vi.fn().mockImplementation((table: string) => makeBuilder(table)),
+    rpc,
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   } as any
 }
@@ -56,9 +62,7 @@ describe('generateGeneralLedger', () => {
         { data: { period_start: '2024-01-01', period_end: '2024-12-31', opening_balance_entry_id: null }, error: null },
       ],
       journal_entry_lines: [
-        // prior lines (from getOpeningBalances fallback) — empty
-        { data: [], error: null },
-        // period lines — empty
+        // period lines — empty (prior lines come from RPC, defaults to empty)
         { data: [], error: null },
       ],
     }
@@ -74,8 +78,6 @@ describe('generateGeneralLedger', () => {
         { data: { period_start: '2024-01-01', period_end: '2024-12-31', opening_balance_entry_id: null }, error: null },
       ],
       journal_entry_lines: [
-        // prior lines — empty (first year)
-        { data: [], error: null },
         // period lines (joined with entry data)
         {
           data: [
@@ -127,14 +129,13 @@ describe('generateGeneralLedger', () => {
       fiscal_periods: [
         { data: { period_start: '2025-01-01', period_end: '2025-12-31', opening_balance_entry_id: null }, error: null },
       ],
-      journal_entry_lines: [
-        // prior lines (from getOpeningBalances fallback)
+      'rpc:compute_prior_opening_balances': [
         {
-          data: [
-            { account_number: '1930', debit_amount: 10000, credit_amount: 0 },
-          ],
+          data: [{ account_number: '1930', debit: 10000, credit: 0 }],
           error: null,
         },
+      ],
+      journal_entry_lines: [
         // period lines
         {
           data: [
@@ -169,8 +170,6 @@ describe('generateGeneralLedger', () => {
         { data: { period_start: '2024-01-01', period_end: '2024-12-31', opening_balance_entry_id: null }, error: null },
       ],
       journal_entry_lines: [
-        // prior lines — empty
-        { data: [], error: null },
         // period lines across multiple accounts
         {
           data: [
@@ -198,8 +197,6 @@ describe('generateGeneralLedger', () => {
         { data: { period_start: '2024-01-01', period_end: '2024-12-31', opening_balance_entry_id: null }, error: null },
       ],
       journal_entry_lines: [
-        // prior lines — empty
-        { data: [], error: null },
         // period lines — out of order
         {
           data: [
@@ -230,7 +227,6 @@ describe('generateGeneralLedger', () => {
         { data: { period_start: '2024-01-01', period_end: '2024-12-31', opening_balance_entry_id: null }, error: null },
       ],
       journal_entry_lines: [
-        { data: [], error: null },
         {
           data: [
             { account_number: '1930', debit_amount: 33.33, credit_amount: 0, journal_entries: { entry_date: '2024-01-15', voucher_number: 1, voucher_series: 'A', description: 'Precision', source_type: 'manual' } },
diff --git a/lib/reports/__tests__/opening-balances.test.ts b/lib/reports/__tests__/opening-balances.test.ts
index 387944e0..5bd181a5 100644
--- a/lib/reports/__tests__/opening-balances.test.ts
+++ b/lib/reports/__tests__/opening-balances.test.ts
@@ -9,8 +9,13 @@ import { fetchAllRows } from '@/lib/supabase/fetch-all'
 
 const mockFetchAllRows = vi.mocked(fetchAllRows)
 
-// eslint-disable-next-line @typescript-eslint/no-explicit-any
-const supabase = {} as any
+function createSupabaseWithRpc(
+  rpcImpl: (fn: string, args: Record<string, unknown>) => Promise<{ data: unknown; error: unknown }>
+) {
+  const rpc = vi.fn(rpcImpl)
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  return { rpc } as any
+}
 
 beforeEach(() => {
   vi.clearAllMocks()
@@ -18,6 +23,8 @@ beforeEach(() => {
 
 describe('getOpeningBalances', () => {
   it('returns empty map and null obEntryId when period is null', async () => {
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    const supabase = {} as any
     const { balances, obEntryId } = await getOpeningBalances(supabase, 'company-1', null)
 
     expect(balances.size).toBe(0)
@@ -31,6 +38,8 @@ describe('getOpeningBalances', () => {
     }
 
     it('returns balances from the OB entry lines', async () => {
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      const supabase = {} as any
       mockFetchAllRows.mockResolvedValue([
         { account_number: '1930', debit_amount: 50000, credit_amount: 0 },
         { account_number: '2440', debit_amount: 0, credit_amount: 10000 },
@@ -44,6 +53,8 @@ describe('getOpeningBalances', () => {
     })
 
     it('aggregates multiple lines for the same account', async () => {
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      const supabase = {} as any
       mockFetchAllRows.mockResolvedValue([
         { account_number: '1930', debit_amount: 30000, credit_amount: 0 },
         { account_number: '1930', debit_amount: 20000, credit_amount: 0 },
@@ -55,6 +66,8 @@ describe('getOpeningBalances', () => {
     })
 
     it('returns the obEntryId string', async () => {
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      const supabase = {} as any
       mockFetchAllRows.mockResolvedValue([])
 
       const { obEntryId } = await getOpeningBalances(supabase, 'company-1', period)
@@ -63,77 +76,95 @@ describe('getOpeningBalances', () => {
     })
   })
 
-  describe('without opening_balance_entry_id (fallback path)', () => {
+  describe('without opening_balance_entry_id (fallback path via RPC)', () => {
     const period = {
       period_start: '2025-01-01',
       opening_balance_entry_id: null,
     }
 
-    it('carries forward balance sheet accounts (class 1-2) only', async () => {
-      mockFetchAllRows.mockResolvedValue([
-        { account_number: '1930', debit_amount: 100000, credit_amount: 5000 },
-        { account_number: '2440', debit_amount: 0, credit_amount: 25000 },
-        // P&L accounts (class 3-8) must NOT carry forward — they reset
-        // to zero each fiscal year via årets resultat.
-        { account_number: '3001', debit_amount: 0, credit_amount: 80000 },
-        { account_number: '5410', debit_amount: 12000, credit_amount: 0 },
-        { account_number: '8310', debit_amount: 0, credit_amount: 1500 },
-      ])
+    it('calls compute_prior_opening_balances RPC with the right args', async () => {
+      const supabase = createSupabaseWithRpc(async () => ({ data: [], error: null }))
+
+      await getOpeningBalances(supabase, 'company-1', period)
+
+      expect(supabase.rpc).toHaveBeenCalledTimes(1)
+      expect(supabase.rpc).toHaveBeenCalledWith('compute_prior_opening_balances', {
+        p_company_id: 'company-1',
+        p_period_start: '2025-01-01',
+      })
+    })
+
+    it('does NOT call the RPC when an OB entry is present', async () => {
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      const supabase = { rpc: vi.fn() } as any
+      mockFetchAllRows.mockResolvedValue([])
+
+      await getOpeningBalances(supabase, 'company-1', {
+        period_start: '2025-01-01',
+        opening_balance_entry_id: 'ob-entry-999',
+      })
+
+      expect(supabase.rpc).not.toHaveBeenCalled()
+    })
+
+    it('maps RPC rows to the balances map', async () => {
+      const supabase = createSupabaseWithRpc(async () => ({
+        data: [
+          { account_number: '1930', debit: 100000, credit: 5000 },
+          { account_number: '2440', debit: 0, credit: 25000 },
+          { account_number: '1510', debit: 8000, credit: 1000 },
+        ],
+        error: null,
+      }))
 
       const { balances, obEntryId } = await getOpeningBalances(supabase, 'company-1', period)
 
       expect(balances.get('1930')).toEqual({ debit: 100000, credit: 5000 })
       expect(balances.get('2440')).toEqual({ debit: 0, credit: 25000 })
-      expect(balances.has('3001')).toBe(false)
-      expect(balances.has('5410')).toBe(false)
-      expect(balances.has('8310')).toBe(false)
-      expect(obEntryId).toBeNull()
-    })
-
-    it('does not accumulate P&L across multi-year SIE imports', async () => {
-      // Simulates importing SIE files for 2022 and 2023, then opening 2024:
-      // BS movements over both years should net to a single IB; P&L from
-      // both years must be discarded.
-      mockFetchAllRows.mockResolvedValue([
-        // 2022 IB + activity on a BS account
-        { account_number: '1930', debit_amount: 50000, credit_amount: 0 },
-        { account_number: '1930', debit_amount: 30000, credit_amount: 10000 },
-        // 2023 activity on the same BS account
-        { account_number: '1930', debit_amount: 20000, credit_amount: 5000 },
-        // 2022 + 2023 P&L activity that previously accumulated incorrectly
-        { account_number: '3001', debit_amount: 0, credit_amount: 200000 },
-        { account_number: '3001', debit_amount: 0, credit_amount: 250000 },
-        { account_number: '5410', debit_amount: 50000, credit_amount: 0 },
-      ])
-
-      const { balances } = await getOpeningBalances(supabase, 'company-1', period)
-
-      expect(balances.get('1930')).toEqual({ debit: 100000, credit: 15000 })
-      expect(balances.has('3001')).toBe(false)
-      expect(balances.has('5410')).toBe(false)
-    })
-
-    it('aggregates multiple lines per account', async () => {
-      mockFetchAllRows.mockResolvedValue([
-        { account_number: '1510', debit_amount: 5000, credit_amount: 0 },
-        { account_number: '1510', debit_amount: 3000, credit_amount: 1000 },
-      ])
-
-      const { balances } = await getOpeningBalances(supabase, 'company-1', period)
-
       expect(balances.get('1510')).toEqual({ debit: 8000, credit: 1000 })
+      expect(obEntryId).toBeNull()
     })
 
-    it('returns null obEntryId', async () => {
-      mockFetchAllRows.mockResolvedValue([])
+    it('returns empty map when RPC returns no rows', async () => {
+      const supabase = createSupabaseWithRpc(async () => ({ data: [], error: null }))
 
-      const { obEntryId } = await getOpeningBalances(supabase, 'company-1', period)
+      const { balances } = await getOpeningBalances(supabase, 'company-1', period)
 
-      expect(obEntryId).toBeNull()
+      expect(balances.size).toBe(0)
+    })
+
+    it('handles RPC returning null data', async () => {
+      const supabase = createSupabaseWithRpc(async () => ({ data: null, error: null }))
+
+      const { balances } = await getOpeningBalances(supabase, 'company-1', period)
+
+      expect(balances.size).toBe(0)
+    })
+
+    it('coerces string-typed numerics (Postgres numeric) to numbers', async () => {
+      const supabase = createSupabaseWithRpc(async () => ({
+        data: [{ account_number: '1930', debit: '12345.67', credit: '0' }],
+        error: null,
+      }))
+
+      const { balances } = await getOpeningBalances(supabase, 'company-1', period)
+
+      expect(balances.get('1930')).toEqual({ debit: 12345.67, credit: 0 })
+    })
+
+    it('throws when the RPC returns an error', async () => {
+      const supabase = createSupabaseWithRpc(async () => ({
+        data: null,
+        error: { message: 'boom' },
+      }))
+
+      await expect(getOpeningBalances(supabase, 'company-1', period)).rejects.toThrow('boom')
     })
   })
 
-  it('coerces null/undefined debit/credit to 0', async () => {
+  it('coerces null/undefined debit/credit to 0 on the OB entry path', async () => {
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    const supabase = {} as any
     const period = {
       period_start: '2025-01-01',
       opening_balance_entry_id: 'ob-entry-1',
@@ -147,17 +178,4 @@ describe('getOpeningBalances', () => {
 
     expect(balances.get('1930')).toEqual({ debit: 0, credit: 0 })
   })
-
-  it('returns empty map when no lines found', async () => {
-    const period = {
-      period_start: '2025-01-01',
-      opening_balance_entry_id: null,
-    }
-
-    mockFetchAllRows.mockResolvedValue([])
-
-    const { balances } = await getOpeningBalances(supabase, 'company-1', period)
-
-    expect(balances.size).toBe(0)
-  })
 })
diff --git a/lib/reports/__tests__/trial-balance.test.ts b/lib/reports/__tests__/trial-balance.test.ts
index e5ddd023..4290b099 100644
--- a/lib/reports/__tests__/trial-balance.test.ts
+++ b/lib/reports/__tests__/trial-balance.test.ts
@@ -25,8 +25,14 @@ function makeBuilder(tableName: string) {
 }
 
 function makeClient() {
+  const rpc = vi.fn().mockImplementation(async (fn: string) => {
+    const queue = mockResults[`rpc:${fn}`]
+    if (!queue || queue.length === 0) return { data: [], error: null }
+    return queue.shift()!
+  })
   return {
     from: vi.fn().mockImplementation((table: string) => makeBuilder(table)),
+    rpc,
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   } as any
 }
@@ -68,9 +74,7 @@ describe('generateTrialBalance', () => {
         { data: { period_start: '2024-01-01', opening_balance_entry_id: null }, error: null },
       ],
       journal_entry_lines: [
-        // prior lines (from getOpeningBalances fallback) — empty for first year
-        { data: [], error: null },
-        // period lines
+        // period lines (prior lines now come from RPC — defaults to empty)
         {
           data: [
             { account_number: '3001', debit_amount: 0, credit_amount: 500 },
@@ -114,15 +118,16 @@ describe('generateTrialBalance', () => {
       fiscal_periods: [
         { data: { period_start: '2025-01-01', opening_balance_entry_id: null }, error: null },
       ],
-      journal_entry_lines: [
-        // prior lines (from getOpeningBalances fallback)
+      'rpc:compute_prior_opening_balances': [
         {
           data: [
-            { account_number: '1930', debit_amount: 10000, credit_amount: 0 },
-            { account_number: '2099', debit_amount: 0, credit_amount: 10000 },
+            { account_number: '1930', debit: 10000, credit: 0 },
+            { account_number: '2099', debit: 0, credit: 10000 },
           ],
           error: null,
         },
+      ],
+      journal_entry_lines: [
         // period lines
         {
           data: [
@@ -232,7 +237,6 @@ describe('generateTrialBalance', () => {
         { data: { period_start: '2024-01-01', opening_balance_entry_id: null }, error: null },
       ],
       journal_entry_lines: [
-        { data: [], error: null },
         {
           data: [
             { account_number: '9999', debit_amount: 100, credit_amount: 0 },
@@ -256,7 +260,6 @@ describe('generateTrialBalance', () => {
         { data: { period_start: '2024-01-01', opening_balance_entry_id: null }, error: null },
       ],
       journal_entry_lines: [
-        { data: [], error: null },
         {
           data: [
             { account_number: '5410', debit_amount: 200, credit_amount: 0 },
@@ -280,7 +283,6 @@ describe('generateTrialBalance', () => {
         { data: { period_start: '2024-01-01', opening_balance_entry_id: null }, error: null },
       ],
       journal_entry_lines: [
-        { data: [], error: null },
         {
           data: [
             { account_number: '1930', debit_amount: 33.33, credit_amount: 0 },
@@ -316,7 +318,6 @@ describe('generateTrialBalance', () => {
         { data: { period_start: '2024-01-01', opening_balance_entry_id: null }, error: null },
       ],
       journal_entry_lines: [
-        { data: [], error: null },
         {
           data: [
             { account_number: '1930', debit_amount: 1000, credit_amount: 0 },
@@ -349,7 +350,6 @@ describe('generateTrialBalance', () => {
         { data: { period_start: '2024-01-01', opening_balance_entry_id: null }, error: null },
       ],
       journal_entry_lines: [
-        { data: [], error: null },
         { data: null, error: { message: 'DB error' } },
       ],
     }
@@ -363,7 +363,6 @@ describe('generateTrialBalance', () => {
         { data: { period_start: '2024-01-01', opening_balance_entry_id: null }, error: null },
       ],
       journal_entry_lines: [
-        { data: [], error: null },
         {
           data: [
             { account_number: '1930', debit_amount: 5000, credit_amount: 0 },
diff --git a/lib/reports/opening-balances.ts b/lib/reports/opening-balances.ts
index 9f0f8a24..7e552ba4 100644
--- a/lib/reports/opening-balances.ts
+++ b/lib/reports/opening-balances.ts
@@ -5,9 +5,10 @@ import { fetchAllRows } from '@/lib/supabase/fetch-all'
  * Get opening balances (ingående balans) for a fiscal period.
  *
  * Uses the opening_balance_entry set by year-end closing when available
- * (O(accounts) — typically ~50 rows). Falls back to summing all entries
- * prior to the period start date via a joined query (O(all_prior_lines) —
- * expensive for companies that haven't run year-end closing).
+ * (O(accounts) — typically ~50 rows). Falls back to a server-side
+ * aggregate via the compute_prior_opening_balances RPC when no OB entry
+ * is set, which returns one row per balance-sheet account (class 1-2)
+ * regardless of how many prior journal lines there are.
  *
  * Returns per-account debit/credit opening balances and the OB entry ID
  * (if any) so the caller can exclude it from period queries to prevent
@@ -59,35 +60,28 @@ export async function getOpeningBalances(
       balances.set(line.account_number, existing)
     }
   } else {
-    // Fallback: compute from all entries dated before this period's start.
-    // This is expensive for multi-year companies that haven't run year-end
-    // closing — consider prompting the user to close prior periods.
-    const priorLines = await fetchAllRows<{
+    // Fallback: server-side aggregate of all prior posted/reversed lines.
+    // The RPC filters to balance-sheet accounts (class 1-2) and returns
+    // one row per account. P&L accounts (class 3-8) reset to zero at each
+    // year transition — their balances are absorbed into årets resultat
+    // (2099) and rolled into equity, so carrying them forward as IB would
+    // violate BFNAR 2013:2. Filtering them in SQL keeps the payload small
+    // and the round-trip count at one regardless of history size.
+    const { data: priorRows, error } = await supabase.rpc('compute_prior_opening_balances', {
+      p_company_id: companyId,
+      p_period_start: period.period_start,
+    })
+    if (error) throw new Error(error.message)
+
+    for (const row of (priorRows ?? []) as Array<{
       account_number: string
-      debit_amount: number
-      credit_amount: number
-    }>(({ from, to }) =>
-      supabase
-        .from('journal_entry_lines')
-        .select('account_number, debit_amount, credit_amount, journal_entries!inner(company_id, status, entry_date)')
-        .eq('journal_entries.company_id', companyId)
-        .in('journal_entries.status', ['posted', 'reversed'])
-        .lt('journal_entries.entry_date', period.period_start)
-        .range(from, to)
-    )
-
-    for (const line of priorLines) {
-      // P&L accounts (class 3-8) reset to zero at each year transition —
-      // their balances are absorbed into årets resultat (2099) and rolled
-      // into equity. Carrying them forward as IB causes resultatkonton to
-      // accumulate across years (BFNAR 2013:2 violation).
-      const cls = parseInt(line.account_number.charAt(0), 10)
-      if (cls >= 3 && cls <= 8) continue
-
-      const existing = balances.get(line.account_number) || { debit: 0, credit: 0 }
-      existing.debit += Number(line.debit_amount) || 0
-      existing.credit += Number(line.credit_amount) || 0
-      balances.set(line.account_number, existing)
+      debit: number | string
+      credit: number | string
+    }>) {
+      balances.set(row.account_number, {
+        debit: Number(row.debit) || 0,
+        credit: Number(row.credit) || 0,
+      })
     }
   }
 
diff --git a/scripts/repair-company-ib-duplicates.ts b/scripts/repair-company-ib-duplicates.ts
new file mode 100644
index 00000000..b18767b3
--- /dev/null
+++ b/scripts/repair-company-ib-duplicates.ts
@@ -0,0 +1,295 @@
+#!/usr/bin/env npx tsx
+/**
+ * Repair redundant opening-balance (IB) entries from multi-year SIE imports.
+ *
+ * Problem: the pre-fix SIE import created one posted journal entry with
+ * source_type='opening_balance' for every year imported. Year N+1's IB
+ * equals year N's UB, which is already the sum of year N's transactions —
+ * so summing prior lines to derive a cumulative balance double-counts one
+ * year of movements per extra IB. Result: cash and other balance-sheet
+ * accounts drift upward each year.
+ *
+ * Fix (per-company): keep the earliest IB entry as the company's pre-system
+ * starting capital; storno (reverse) every later IB entry. The immutability
+ * trigger on journal_entries blocks DELETE of posted entries, so storno is
+ * the only legally-compliant path (BFL / BFNAR 2013:2).
+ *
+ * Side effect: the storno'd period's fiscal_periods.opening_balance_entry_id
+ * link is cleared so getOpeningBalances() falls through to the duplicate-
+ * safe compute_prior_opening_balances RPC for that period.
+ *
+ * Also handles the "start over" case via --purge-imports:
+ *   - Storno every SIE-origin journal entry for the company.
+ *   - Delete sie_imports rows so their (company_id, file_hash) pairs free up.
+ *   - Leaves fiscal periods in place (they may host manual entries too).
+ *
+ * Usage:
+ *   # Preview IB dedup only
+ *   npx tsx scripts/repair-company-ib-duplicates.ts \
+ *     --company-id <uuid> --user-id <uuid>
+ *
+ *   # Apply IB dedup
+ *   npx tsx scripts/repair-company-ib-duplicates.ts \
+ *     --company-id <uuid> --user-id <uuid> --commit
+ *
+ *   # Preview full purge (IBs + all SIE-origin entries + sie_imports rows)
+ *   npx tsx scripts/repair-company-ib-duplicates.ts \
+ *     --company-id <uuid> --user-id <uuid> --purge-imports
+ */
+
+import { config } from 'dotenv'
+config({ path: '.env.local' })
+import { createClient, type SupabaseClient } from '@supabase/supabase-js'
+import { reverseEntry } from '../lib/bookkeeping/engine'
+
+// ──────────────────────────────────────────────────────────────────
+// Args
+// ──────────────────────────────────────────────────────────────────
+
+function arg(name: string): string | undefined {
+  const i = process.argv.indexOf(`--${name}`)
+  return i >= 0 ? process.argv[i + 1] : undefined
+}
+
+const COMPANY_ID = arg('company-id')
+const USER_ID = arg('user-id')
+const COMMIT = process.argv.includes('--commit')
+const PURGE_IMPORTS = process.argv.includes('--purge-imports')
+
+if (!COMPANY_ID || !USER_ID) {
+  console.error(
+    'Usage: npx tsx scripts/repair-company-ib-duplicates.ts --company-id <uuid> --user-id <uuid> [--purge-imports] [--commit]'
+  )
+  process.exit(1)
+}
+
+const supabaseUrl = process.env.NEXT_PUBLIC_SUPABASE_URL
+const serviceRoleKey = process.env.SUPABASE_SERVICE_ROLE_KEY
+
+if (!supabaseUrl || !serviceRoleKey) {
+  console.error('Missing NEXT_PUBLIC_SUPABASE_URL or SUPABASE_SERVICE_ROLE_KEY in .env.local')
+  process.exit(1)
+}
+
+const supabase = createClient(supabaseUrl, serviceRoleKey) as SupabaseClient
+
+// ──────────────────────────────────────────────────────────────────
+// Banner
+// ──────────────────────────────────────────────────────────────────
+
+console.log('─────────────────────────────────────────────────────────')
+console.log('IB Duplicate Repair')
+console.log('─────────────────────────────────────────────────────────')
+console.log('Supabase URL :', supabaseUrl)
+console.log('Company      :', COMPANY_ID)
+console.log('User         :', USER_ID)
+console.log('Mode         :', COMMIT ? 'COMMIT (writes)' : 'DRY RUN (no writes)')
+console.log('Purge imports:', PURGE_IMPORTS ? 'YES (also storno SIE-origin entries)' : 'NO')
+console.log('─────────────────────────────────────────────────────────\n')
+
+// ──────────────────────────────────────────────────────────────────
+// IB dedup
+// ──────────────────────────────────────────────────────────────────
+
+interface IbRow {
+  id: string
+  fiscal_period_id: string | null
+  entry_date: string
+  created_at: string
+  voucher_series: string | null
+  voucher_number: number | null
+}
+
+async function listPostedIbEntries(): Promise<IbRow[]> {
+  const { data, error } = await supabase
+    .from('journal_entries')
+    .select('id, fiscal_period_id, entry_date, created_at, voucher_series, voucher_number')
+    .eq('company_id', COMPANY_ID!)
+    .eq('source_type', 'opening_balance')
+    .eq('status', 'posted')
+    .order('entry_date', { ascending: true })
+    .order('created_at', { ascending: true })
+
+  if (error) throw new Error(`Failed to list IB entries: ${error.message}`)
+  return (data as IbRow[]) ?? []
+}
+
+async function unlinkFromFiscalPeriod(entryId: string): Promise<void> {
+  const { error } = await supabase
+    .from('fiscal_periods')
+    .update({ opening_balance_entry_id: null, opening_balances_set: false })
+    .eq('company_id', COMPANY_ID!)
+    .eq('opening_balance_entry_id', entryId)
+
+  if (error) throw new Error(`Failed to unlink fiscal_periods.opening_balance_entry_id: ${error.message}`)
+}
+
+async function stornoIbDuplicates(): Promise<{ kept: IbRow | null; stornoed: number; failed: number }> {
+  console.log('[1/2] IB dedup')
+  const ibs = await listPostedIbEntries()
+  console.log(`  · Found ${ibs.length} posted opening_balance entries`)
+
+  if (ibs.length === 0) {
+    console.log('  · Nothing to do.')
+    return { kept: null, stornoed: 0, failed: 0 }
+  }
+
+  const [earliest, ...redundant] = ibs
+
+  console.log(
+    `  · Keeping earliest IB: ${earliest.id} on ${earliest.entry_date} ` +
+    `(series ${earliest.voucher_series ?? '?'} #${earliest.voucher_number ?? '?'})`
+  )
+  for (const r of redundant) {
+    console.log(
+      `  · Will storno: ${r.id} on ${r.entry_date} ` +
+      `(series ${r.voucher_series ?? '?'} #${r.voucher_number ?? '?'})`
+    )
+  }
+
+  if (!COMMIT) {
+    console.log('  · [dry-run] skipping storno and unlink')
+    return { kept: earliest, stornoed: 0, failed: 0 }
+  }
+
+  let stornoed = 0
+  let failed = 0
+  for (const r of redundant) {
+    try {
+      await unlinkFromFiscalPeriod(r.id)
+      await reverseEntry(supabase, COMPANY_ID!, USER_ID!, r.id)
+      console.log(`  · Stornoed ${r.id}`)
+      stornoed++
+    } catch (err) {
+      console.error(`  · FAILED to storno ${r.id}:`, err instanceof Error ? err.message : err)
+      failed++
+    }
+  }
+
+  return { kept: earliest, stornoed, failed }
+}
+
+// ──────────────────────────────────────────────────────────────────
+// Optional full SIE purge (for "start over" scenario)
+// ──────────────────────────────────────────────────────────────────
+
+interface SieImportRow {
+  id: string
+  filename: string | null
+  file_hash: string | null
+  fiscal_period_id: string | null
+  status: string | null
+  imported_at: string | null
+}
+
+async function listSieImports(): Promise<SieImportRow[]> {
+  const { data, error } = await supabase
+    .from('sie_imports')
+    .select('id, filename, file_hash, fiscal_period_id, status, imported_at')
+    .eq('company_id', COMPANY_ID!)
+    .order('imported_at', { ascending: true })
+
+  if (error) throw new Error(`Failed to list sie_imports: ${error.message}`)
+  return (data as SieImportRow[]) ?? []
+}
+
+async function listSieOriginEntries(periodIds: string[]): Promise<{ id: string; voucher_number: number | null; entry_date: string }[]> {
+  if (periodIds.length === 0) return []
+  const { data, error } = await supabase
+    .from('journal_entries')
+    .select('id, voucher_number, entry_date, fiscal_period_id, source_type, status')
+    .eq('company_id', COMPANY_ID!)
+    .in('fiscal_period_id', periodIds)
+    .eq('status', 'posted')
+    .in('source_type', ['import', 'opening_balance'])
+
+  if (error) throw new Error(`Failed to list SIE-origin entries: ${error.message}`)
+  return (data as { id: string; voucher_number: number | null; entry_date: string }[]) ?? []
+}
+
+async function purgeSieImports(): Promise<void> {
+  console.log('\n[2/2] SIE import purge')
+  const imports = await listSieImports()
+  console.log(`  · Found ${imports.length} sie_imports rows`)
+
+  if (imports.length === 0) {
+    console.log('  · Nothing to purge.')
+    return
+  }
+
+  const periodIds = Array.from(new Set(imports.map((i) => i.fiscal_period_id).filter((p): p is string => !!p)))
+  const entries = await listSieOriginEntries(periodIds)
+  console.log(`  · Found ${entries.length} posted entries in affected fiscal periods (${periodIds.length} periods)`)
+
+  for (const imp of imports) {
+    console.log(
+      `  · Will remove sie_imports row ${imp.id} (${imp.filename ?? 'unnamed'}, file_hash ${imp.file_hash?.slice(0, 12) ?? '?'}…)`
+    )
+  }
+
+  if (!COMMIT) {
+    console.log('  · [dry-run] skipping storno and sie_imports delete')
+    return
+  }
+
+  let stornoed = 0
+  let failed = 0
+  for (const e of entries) {
+    try {
+      await supabase
+        .from('fiscal_periods')
+        .update({ opening_balance_entry_id: null, opening_balances_set: false })
+        .eq('company_id', COMPANY_ID!)
+        .eq('opening_balance_entry_id', e.id)
+      await reverseEntry(supabase, COMPANY_ID!, USER_ID!, e.id)
+      stornoed++
+    } catch (err) {
+      console.error(`  · FAILED to storno entry ${e.id}:`, err instanceof Error ? err.message : err)
+      failed++
+    }
+  }
+  console.log(`  · Stornoed ${stornoed}/${entries.length} entries (${failed} failed)`)
+
+  const { error: delErr } = await supabase
+    .from('sie_imports')
+    .delete()
+    .eq('company_id', COMPANY_ID!)
+
+  if (delErr) {
+    console.error(`  · FAILED to delete sie_imports rows: ${delErr.message}`)
+  } else {
+    console.log(`  · Deleted ${imports.length} sie_imports rows`)
+  }
+}
+
+// ──────────────────────────────────────────────────────────────────
+// Main
+// ──────────────────────────────────────────────────────────────────
+
+async function main() {
+  try {
+    const ibResult = await stornoIbDuplicates()
+
+    if (PURGE_IMPORTS) {
+      await purgeSieImports()
+    }
+
+    console.log('\n─────────────────────────────────────────────────────────')
+    console.log('Summary')
+    console.log('─────────────────────────────────────────────────────────')
+    if (ibResult.kept) {
+      console.log(`Kept IB entry   : ${ibResult.kept.id} (${ibResult.kept.entry_date})`)
+    }
+    console.log(`IBs stornoed    : ${ibResult.stornoed}`)
+    console.log(`IB storno fails : ${ibResult.failed}`)
+    console.log(`Mode            : ${COMMIT ? 'COMMIT' : 'DRY RUN'}`)
+    if (!COMMIT) {
+      console.log('\nRe-run with --commit to apply.')
+    }
+  } catch (err) {
+    console.error('\nFATAL:', err instanceof Error ? err.message : err)
+    process.exit(1)
+  }
+}
+
+main()
diff --git a/scripts/repair-fiscal-period-chain.ts b/scripts/repair-fiscal-period-chain.ts
new file mode 100644
index 00000000..0740e70d
--- /dev/null
+++ b/scripts/repair-fiscal-period-chain.ts
@@ -0,0 +1,340 @@
+#!/usr/bin/env npx tsx
+/**
+ * One-off repair for a company whose fiscal period chain was broken by
+ * the pre-fix "change fiscal year" flow: a newer period was created
+ * without previous_period_id and without an opening_balance_entry_id,
+ * so the balance sheet falls back to a full-history scan (and times out
+ * on production with 8k+ prior lines).
+ *
+ * Target state expected (validated before running):
+ *
+ *   Prior period (e.g. 2024/2025): open, has entries, no closing_entry_id.
+ *   Gap:                          Sep-Dec 2025, zero entries.
+ *   Orphan period (e.g. 2026):    previous_period_id=NULL,
+ *                                 opening_balance_entry_id=NULL,
+ *                                 zero entries.
+ *
+ * End state:
+ *
+ *   Prior period: year-end-closed (locked, closing_entry_id, is_closed).
+ *   Short period: Sep-Dec 2025, previous_period_id=prior,
+ *                 opening_balance_entry_id set, locked.
+ *   Orphan period: previous_period_id=short, opening_balance_entry_id set.
+ *
+ * Usage:
+ *   npx tsx scripts/repair-fiscal-period-chain.ts \
+ *     --company-id <uuid> --user-id <uuid> --prior <uuid> --orphan <uuid> \
+ *     [--short-start 2025-09-01] [--short-end 2025-12-31] \
+ *     [--commit]   # default is --dry-run
+ */
+
+import { config } from 'dotenv'
+config({ path: '.env.local' })
+import { createClient } from '@supabase/supabase-js'
+import {
+  previewYearEndClosing,
+  generateOpeningBalances,
+} from '../lib/core/bookkeeping/year-end-service'
+import { validateBalanceContinuity } from '../lib/reports/continuity-check'
+import { lockPeriod } from '../lib/core/bookkeeping/period-service'
+import { executeCurrencyRevaluation } from '../lib/bookkeeping/currency-revaluation'
+import { createJournalEntry } from '../lib/bookkeeping/engine'
+
+// ────────────────────────────────────────────────────────────────────
+// Args
+// ────────────────────────────────────────────────────────────────────
+
+function arg(name: string): string | undefined {
+  const i = process.argv.indexOf(`--${name}`)
+  return i >= 0 ? process.argv[i + 1] : undefined
+}
+
+const COMPANY_ID = arg('company-id')
+const USER_ID = arg('user-id')
+const PRIOR_ID = arg('prior')
+const ORPHAN_ID = arg('orphan')
+const SHORT_START = arg('short-start') ?? '2025-09-01'
+const SHORT_END = arg('short-end') ?? '2025-12-31'
+const COMMIT = process.argv.includes('--commit')
+
+if (!COMPANY_ID || !USER_ID || !PRIOR_ID || !ORPHAN_ID) {
+  console.error(
+    'Usage: npx tsx scripts/repair-fiscal-period-chain.ts --company-id <uuid> --user-id <uuid> --prior <uuid> --orphan <uuid> [--short-start 2025-09-01] [--short-end 2025-12-31] [--commit]'
+  )
+  process.exit(1)
+}
+
+const supabaseUrl = process.env.NEXT_PUBLIC_SUPABASE_URL
+const serviceRoleKey = process.env.SUPABASE_SERVICE_ROLE_KEY
+
+if (!supabaseUrl || !serviceRoleKey) {
+  console.error('Missing NEXT_PUBLIC_SUPABASE_URL or SUPABASE_SERVICE_ROLE_KEY in .env.local')
+  process.exit(1)
+}
+
+const supabase = createClient(supabaseUrl, serviceRoleKey)
+
+// ────────────────────────────────────────────────────────────────────
+// Banner
+// ────────────────────────────────────────────────────────────────────
+
+console.log('─────────────────────────────────────────────────────────')
+console.log('Fiscal Period Chain Repair')
+console.log('─────────────────────────────────────────────────────────')
+console.log('Supabase URL :', supabaseUrl)
+console.log('Company      :', COMPANY_ID)
+console.log('User         :', USER_ID)
+console.log('Prior period :', PRIOR_ID)
+console.log('Orphan period:', ORPHAN_ID)
+console.log('Short period :', `${SHORT_START} → ${SHORT_END}`)
+console.log('Mode         :', COMMIT ? 'COMMIT (writes)' : 'DRY RUN (no writes)')
+console.log('─────────────────────────────────────────────────────────\n')
+
+// ────────────────────────────────────────────────────────────────────
+// Validate state
+// ────────────────────────────────────────────────────────────────────
+
+async function validateState() {
+  const { data: prior } = await supabase
+    .from('fiscal_periods')
+    .select('*')
+    .eq('id', PRIOR_ID)
+    .eq('company_id', COMPANY_ID)
+    .single()
+
+  if (!prior) throw new Error(`Prior period ${PRIOR_ID} not found for company ${COMPANY_ID}`)
+  if (prior.is_closed) throw new Error('Prior period is already closed')
+  if (prior.closing_entry_id) throw new Error('Prior period already has closing_entry_id')
+
+  const { data: orphan } = await supabase
+    .from('fiscal_periods')
+    .select('*')
+    .eq('id', ORPHAN_ID)
+    .eq('company_id', COMPANY_ID)
+    .single()
+
+  if (!orphan) throw new Error(`Orphan period ${ORPHAN_ID} not found for company ${COMPANY_ID}`)
+  if (orphan.previous_period_id)
+    throw new Error(`Orphan period already has previous_period_id = ${orphan.previous_period_id}`)
+  if (orphan.opening_balance_entry_id)
+    throw new Error('Orphan period already has opening_balance_entry_id')
+
+  // Gap check: zero entries between prior end and short end
+  const { count: gapCount } = await supabase
+    .from('journal_entries')
+    .select('id', { count: 'exact', head: true })
+    .eq('company_id', COMPANY_ID)
+    .gt('entry_date', prior.period_end)
+    .lte('entry_date', SHORT_END)
+    .in('status', ['posted', 'reversed'])
+
+  if ((gapCount ?? 0) > 0)
+    throw new Error(
+      `Gap between ${prior.period_end} and ${SHORT_END} has ${gapCount} entries — repair assumes zero activity in gap`
+    )
+
+  // Orphan must be empty
+  const { count: orphanEntries } = await supabase
+    .from('journal_entries')
+    .select('id', { count: 'exact', head: true })
+    .eq('company_id', COMPANY_ID)
+    .eq('fiscal_period_id', ORPHAN_ID)
+    .in('status', ['posted', 'reversed'])
+
+  if ((orphanEntries ?? 0) > 0)
+    throw new Error(`Orphan period has ${orphanEntries} posted entries — not safe to repair automatically`)
+
+  // Short period dates must be contiguous with prior
+  const nextAfterPrior = new Date(prior.period_end + 'T12:00:00Z')
+  nextAfterPrior.setUTCDate(nextAfterPrior.getUTCDate() + 1)
+  const expected = nextAfterPrior.toISOString().split('T')[0]
+  if (expected !== SHORT_START)
+    throw new Error(`--short-start ${SHORT_START} must equal ${expected} (day after prior.period_end)`)
+
+  // Short end must be day before orphan start
+  const beforeOrphan = new Date(orphan.period_start + 'T12:00:00Z')
+  beforeOrphan.setUTCDate(beforeOrphan.getUTCDate() - 1)
+  const expectedEnd = beforeOrphan.toISOString().split('T')[0]
+  if (expectedEnd !== SHORT_END)
+    throw new Error(`--short-end ${SHORT_END} must equal ${expectedEnd} (day before orphan.period_start)`)
+
+  return { prior, orphan }
+}
+
+// ────────────────────────────────────────────────────────────────────
+// Steps
+// ────────────────────────────────────────────────────────────────────
+
+async function step1YearEndPrior(priorEnd: string) {
+  console.log('\n[1/7] Year-end closing on prior period')
+
+  console.log('  · Currency revaluation preview')
+  if (COMMIT) {
+    await executeCurrencyRevaluation(supabase, COMPANY_ID!, priorEnd, PRIOR_ID!, USER_ID!)
+  }
+
+  console.log('  · Building closing entry preview')
+  const preview = await previewYearEndClosing(supabase, COMPANY_ID!, USER_ID!, PRIOR_ID!)
+  console.log(`    net result: ${preview.netResult} → ${preview.closingAccount}`)
+  console.log(`    ${preview.closingLines.length} closing lines`)
+
+  if (preview.closingLines.length === 0) {
+    throw new Error('No result accounts to close — prior period has no activity')
+  }
+
+  if (!COMMIT) {
+    console.log('  · [dry-run] skipping createJournalEntry, update, lock, close')
+    return { closingEntryId: '<dry-run>' }
+  }
+
+  console.log('  · Creating closing entry')
+  const closingEntry = await createJournalEntry(supabase, COMPANY_ID!, USER_ID!, {
+    fiscal_period_id: PRIOR_ID!,
+    entry_date: priorEnd,
+    description: 'Årsbokslut (repair)',
+    source_type: 'year_end',
+    voucher_series: 'A',
+    lines: preview.closingLines,
+  })
+
+  await supabase
+    .from('fiscal_periods')
+    .update({ closing_entry_id: closingEntry.id })
+    .eq('id', PRIOR_ID!)
+    .eq('company_id', COMPANY_ID!)
+
+  console.log('  · Locking and closing prior period')
+  await lockPeriod(supabase, COMPANY_ID!, USER_ID!, PRIOR_ID!)
+  await supabase
+    .from('fiscal_periods')
+    .update({ is_closed: true, closed_at: new Date().toISOString() })
+    .eq('id', PRIOR_ID!)
+    .eq('company_id', COMPANY_ID!)
+
+  return { closingEntryId: closingEntry.id }
+}
+
+async function step2InsertShortPeriod() {
+  console.log('\n[2/7] Inserting short transition period')
+  console.log(`  · ${SHORT_START} → ${SHORT_END}`)
+
+  if (!COMMIT) {
+    console.log('  · [dry-run] skipping insert')
+    return '<dry-run>'
+  }
+
+  const { data, error } = await supabase
+    .from('fiscal_periods')
+    .insert({
+      company_id: COMPANY_ID!,
+      user_id: USER_ID!,
+      name: `Transition ${SHORT_START.slice(0, 7)}–${SHORT_END.slice(0, 7)}`,
+      period_start: SHORT_START,
+      period_end: SHORT_END,
+      previous_period_id: PRIOR_ID!,
+    })
+    .select()
+    .single()
+
+  if (error || !data) throw new Error(`Failed to insert short period: ${error?.message}`)
+  console.log(`  · Short period id: ${data.id}`)
+  return data.id as string
+}
+
+async function step3GenerateShortOb(shortPeriodId: string) {
+  console.log('\n[3/7] Generating OB entry on short period (carries forward from prior)')
+  if (!COMMIT) {
+    console.log('  · [dry-run] skipping generateOpeningBalances')
+    return '<dry-run>'
+  }
+  const ob = await generateOpeningBalances(supabase, COMPANY_ID!, USER_ID!, PRIOR_ID!, shortPeriodId)
+  console.log(`  · OB entry id: ${ob.id}`)
+  return ob.id
+}
+
+async function step4LockShort(shortPeriodId: string) {
+  console.log('\n[4/7] Locking short period (no period activity to close)')
+  if (!COMMIT) {
+    console.log('  · [dry-run] skipping lockPeriod')
+    return
+  }
+  await lockPeriod(supabase, COMPANY_ID!, USER_ID!, shortPeriodId)
+}
+
+async function step5LinkOrphan(shortPeriodId: string) {
+  console.log('\n[5/7] Linking orphan period to short period')
+  if (!COMMIT) {
+    console.log('  · [dry-run] skipping update orphan.previous_period_id')
+    return
+  }
+  const { error } = await supabase
+    .from('fiscal_periods')
+    .update({ previous_period_id: shortPeriodId })
+    .eq('id', ORPHAN_ID!)
+    .eq('company_id', COMPANY_ID!)
+  if (error) throw new Error(`Failed to link orphan: ${error.message}`)
+}
+
+async function step6GenerateOrphanOb(shortPeriodId: string) {
+  console.log('\n[6/7] Generating OB entry on orphan period (carries forward from short)')
+  if (!COMMIT) {
+    console.log('  · [dry-run] skipping generateOpeningBalances')
+    return '<dry-run>'
+  }
+  const ob = await generateOpeningBalances(supabase, COMPANY_ID!, USER_ID!, shortPeriodId, ORPHAN_ID!)
+  console.log(`  · OB entry id: ${ob.id}`)
+  return ob.id
+}
+
+async function step7Continuity() {
+  console.log('\n[7/7] Validating IB/UB continuity on orphan period')
+  if (!COMMIT) {
+    console.log('  · [dry-run] skipping continuity check')
+    return
+  }
+  const result = await validateBalanceContinuity(supabase, COMPANY_ID!, ORPHAN_ID!)
+  console.log(`  · valid: ${result.valid}, checked: ${result.checked_accounts} accounts`)
+  if (!result.valid) {
+    console.log('  · discrepancies:')
+    for (const d of result.discrepancies) {
+      console.log(`    ${d.account_number}: UB=${d.previous_ub_net}, IB=${d.current_ib_net}, diff=${d.difference}`)
+    }
+  }
+  await supabase
+    .from('fiscal_periods')
+    .update({ continuity_verified: result.valid })
+    .eq('id', ORPHAN_ID!)
+    .eq('company_id', COMPANY_ID!)
+}
+
+// ────────────────────────────────────────────────────────────────────
+// Run
+// ────────────────────────────────────────────────────────────────────
+
+async function main() {
+  const { prior } = await validateState()
+  console.log(`✓ Validated state — prior '${prior.name}' (${prior.period_start} → ${prior.period_end})`)
+
+  const { closingEntryId } = await step1YearEndPrior(prior.period_end)
+  const shortPeriodId = await step2InsertShortPeriod()
+  const shortObId = await step3GenerateShortOb(shortPeriodId)
+  await step4LockShort(shortPeriodId)
+  await step5LinkOrphan(shortPeriodId)
+  const orphanObId = await step6GenerateOrphanOb(shortPeriodId)
+  await step7Continuity()
+
+  console.log('\n─────────────────────────────────────────────────────────')
+  console.log('Summary')
+  console.log('─────────────────────────────────────────────────────────')
+  console.log('Prior closing entry :', closingEntryId)
+  console.log('Short period id    :', shortPeriodId)
+  console.log('Short OB entry id  :', shortObId)
+  console.log('Orphan OB entry id :', orphanObId)
+  console.log('Mode                :', COMMIT ? 'COMMITTED' : 'DRY RUN (no writes)')
+  console.log('─────────────────────────────────────────────────────────')
+}
+
+main().catch((err) => {
+  console.error('\n✗ Repair failed:', err instanceof Error ? err.message : err)
+  process.exit(1)
+})
diff --git a/supabase/migrations/20260421160000_opening_balances_rpc.sql b/supabase/migrations/20260421160000_opening_balances_rpc.sql
new file mode 100644
index 00000000..1b78ee51
--- /dev/null
+++ b/supabase/migrations/20260421160000_opening_balances_rpc.sql
@@ -0,0 +1,93 @@
+-- compute_prior_opening_balances(company_id, period_start)
+--
+-- Server-side aggregate for the opening-balances fallback used when a fiscal
+-- period has no opening_balance_entry_id set (i.e. year-end closing never ran
+-- for the prior period). Returns one row per balance-sheet account
+-- (class 1-2) with the summed debit and credit of every posted/reversed
+-- journal line dated before the period start.
+--
+-- Replaces a paginated PostgREST scan that fetched every prior line via
+-- journal_entry_lines with an !inner join on journal_entries. At ~8k lines
+-- that scan would tip over the 8s statement_timeout on the authenticated
+-- role because the RLS EXISTS subquery on journal_entry_lines re-evaluates
+-- user_company_ids() per row on every .range() page. This RPC pushes the
+-- filter + SUM into the planner and returns ~50 rows in a single round trip.
+--
+-- Class 3-8 accounts are intentionally excluded: their balances reset at
+-- each year transition and are absorbed into equity via the closing entry;
+-- carrying them forward as IB would violate BFNAR 2013:2.
+--
+-- Duplicate-IB guard: multi-year SIE imports create one opening_balance
+-- journal entry per imported year (the #IB records from each SIE file).
+-- Each year N+1's IB equals year N's UB, which is already the sum of
+-- year N's journal lines — so blindly summing every prior IB double-counts
+-- by one year's worth of movements per duplicate. Only the earliest IB per
+-- account is kept (pre-system starting capital); later IBs are excluded.
+
+CREATE OR REPLACE FUNCTION compute_prior_opening_balances(
+  p_company_id uuid,
+  p_period_start date
+)
+RETURNS TABLE (account_number text, debit numeric, credit numeric)
+LANGUAGE sql
+STABLE
+SECURITY INVOKER
+SET search_path = public
+AS $$
+  -- Dedup is per-account, not per-entry. If the same account appears in multiple
+  -- IB entries (duplicate opening balances from multi-year imports), we keep only
+  -- the earliest line for that account. Accounts that appear only in a later IB
+  -- (e.g. a new account introduced in year N with no prior-year IB) are still
+  -- included — they represent a genuine pre-system starting balance for that
+  -- account, not a duplicate.
+  WITH ib_lines_ranked AS (
+    SELECT
+      jel.account_number,
+      jel.debit_amount,
+      jel.credit_amount,
+      ROW_NUMBER() OVER (
+        PARTITION BY jel.account_number
+        ORDER BY je.entry_date ASC, je.created_at ASC, je.id ASC
+      ) AS rn
+    FROM journal_entry_lines jel
+    JOIN journal_entries je ON je.id = jel.journal_entry_id
+    WHERE je.company_id = p_company_id
+      AND je.status IN ('posted', 'reversed')
+      AND je.entry_date < p_period_start
+      AND je.source_type = 'opening_balance'
+      AND substr(jel.account_number, 1, 1) BETWEEN '1' AND '2'
+  ),
+  earliest_ib AS (
+    SELECT account_number, debit_amount, credit_amount
+    FROM ib_lines_ranked
+    WHERE rn = 1
+  ),
+  non_ib_lines AS (
+    SELECT
+      jel.account_number,
+      jel.debit_amount,
+      jel.credit_amount
+    FROM journal_entry_lines jel
+    JOIN journal_entries je ON je.id = jel.journal_entry_id
+    WHERE je.company_id = p_company_id
+      AND je.status IN ('posted', 'reversed')
+      AND je.entry_date < p_period_start
+      AND je.source_type IS DISTINCT FROM 'opening_balance'
+      AND substr(jel.account_number, 1, 1) BETWEEN '1' AND '2'
+  ),
+  all_lines AS (
+    SELECT account_number, debit_amount, credit_amount FROM earliest_ib
+    UNION ALL
+    SELECT account_number, debit_amount, credit_amount FROM non_ib_lines
+  )
+  SELECT
+    account_number,
+    SUM(debit_amount)::numeric  AS debit,
+    SUM(credit_amount)::numeric AS credit
+  FROM all_lines
+  GROUP BY account_number;
+$$;
+
+GRANT EXECUTE ON FUNCTION compute_prior_opening_balances(uuid, date) TO authenticated;
+
+NOTIFY pgrst, 'reload schema';
diff --git a/supabase/migrations/20260421170000_commit_journal_entry_user_id_fallback.sql b/supabase/migrations/20260421170000_commit_journal_entry_user_id_fallback.sql
new file mode 100644
index 00000000..6c3417b7
--- /dev/null
+++ b/supabase/migrations/20260421170000_commit_journal_entry_user_id_fallback.sql
@@ -0,0 +1,64 @@
+-- commit_journal_entry: fall back to the draft entry's user_id when
+-- auth.uid() is NULL.
+--
+-- Context: when this RPC is invoked via the service role (one-off repair
+-- scripts, cron jobs, internal maintenance flows), auth.uid() returns NULL.
+-- The INSERT into voucher_sequences then fails its user_id NOT NULL check
+-- *before* ON CONFLICT can resolve to DO UPDATE (PostgreSQL evaluates NOT
+-- NULL on the candidate tuple ahead of conflict arbitration). That made it
+-- impossible to commit journal entries from any non-interactive context.
+--
+-- Fix: read user_id from the draft journal entry (which is always set by
+-- createJournalEntry) and use it as the fallback attribution on the
+-- voucher sequence row. Normal interactive flows still record auth.uid();
+-- only the service-role path changes.
+
+CREATE OR REPLACE FUNCTION public.commit_journal_entry(
+  p_company_id uuid,
+  p_entry_id uuid,
+  p_commit_method text DEFAULT NULL,
+  p_rubric_version text DEFAULT NULL
+)
+RETURNS TABLE (voucher_number integer)
+LANGUAGE plpgsql
+SECURITY DEFINER
+AS $$
+DECLARE
+  v_next integer;
+  v_fiscal_period_id uuid;
+  v_series text;
+  v_entry_user_id uuid;
+BEGIN
+  SELECT je.fiscal_period_id, COALESCE(je.voucher_series, 'A'), je.user_id
+  INTO v_fiscal_period_id, v_series, v_entry_user_id
+  FROM public.journal_entries je
+  WHERE je.id = p_entry_id
+    AND je.company_id = p_company_id
+    AND je.status = 'draft'
+  FOR UPDATE;
+
+  IF NOT FOUND THEN
+    RAISE EXCEPTION 'Draft journal entry not found: %', p_entry_id;
+  END IF;
+
+  INSERT INTO public.voucher_sequences (company_id, user_id, fiscal_period_id, voucher_series, last_number)
+  VALUES (p_company_id, COALESCE(auth.uid(), v_entry_user_id), v_fiscal_period_id, v_series, 1)
+  ON CONFLICT (company_id, fiscal_period_id, voucher_series)
+  DO UPDATE SET
+    last_number = public.voucher_sequences.last_number + 1,
+    updated_at = now()
+  RETURNING last_number INTO v_next;
+
+  UPDATE public.journal_entries
+  SET voucher_number = v_next,
+      status = 'posted',
+      commit_method = p_commit_method,
+      rubric_version = p_rubric_version
+  WHERE id = p_entry_id
+    AND company_id = p_company_id;
+
+  RETURN QUERY SELECT v_next;
+END;
+$$;
+
+NOTIFY pgrst, 'reload schema';
diff --git a/supabase/migrations/20260421180000_opening_balances_rpc_fix_reversed_and_new_accounts.sql b/supabase/migrations/20260421180000_opening_balances_rpc_fix_reversed_and_new_accounts.sql
new file mode 100644
index 00000000..4bb6cca8
--- /dev/null
+++ b/supabase/migrations/20260421180000_opening_balances_rpc_fix_reversed_and_new_accounts.sql
@@ -0,0 +1,110 @@
+-- compute_prior_opening_balances — correctness fixes
+--
+-- Supersedes the function defined in 20260421160000. Addresses two bugs
+-- surfaced in Swedish accounting compliance review:
+--
+-- 1. Reversed entries were previously included in ib_lines_ranked via
+--    status IN ('posted', 'reversed'). Because the per-account ROW_NUMBER
+--    dedup picks the earliest IB line (rn = 1), a cancelled (reversed) IB
+--    could be carried forward as the pre-system starting balance while its
+--    matching storno entry (source_type = 'storno') landed in non_ib_lines
+--    with flipped amounts — producing a net negative skew equal to the
+--    cancelled IB. Now ib_lines_ranked only considers currently-posted IB
+--    entries, and non_ib_lines excludes 'storno' source_type so a cancelled
+--    pair contributes zero on both sides. Per BFL 5:5, the computed IB must
+--    reflect the legally effective net position, not a cancelled entry.
+--
+-- 2. The per-account dedup rule ("keep earliest IB line, drop the rest")
+--    double-counted balances for accounts that first appeared in a later
+--    year's IB but already had prior-year non-IB activity. In a multi-year
+--    SIE import, a year-N IB line equals year-(N-1) UB, which is already
+--    captured in the prior-year transaction lines. The correct rule is:
+--    keep the earliest IB line for an account only if there is no non-IB
+--    activity on that account dated before the IB itself. Otherwise the
+--    IB is a restatement of a UB already derivable from non-IB lines.
+--    This preserves genuine pre-system starting balances for accounts
+--    introduced later (BFNAR 2013:2) while preventing phantom balances.
+
+CREATE OR REPLACE FUNCTION compute_prior_opening_balances(
+  p_company_id uuid,
+  p_period_start date
+)
+RETURNS TABLE (account_number text, debit numeric, credit numeric)
+LANGUAGE sql
+STABLE
+SECURITY INVOKER
+SET search_path = public
+AS $$
+  WITH ib_lines_ranked AS (
+    -- Currently-effective IB lines only. Reversed originals and their stornos
+    -- are both excluded (originals by status, stornos by source_type below).
+    SELECT
+      jel.account_number,
+      jel.debit_amount,
+      jel.credit_amount,
+      je.entry_date,
+      ROW_NUMBER() OVER (
+        PARTITION BY jel.account_number
+        ORDER BY je.entry_date ASC, je.created_at ASC, je.id ASC
+      ) AS rn
+    FROM journal_entry_lines jel
+    JOIN journal_entries je ON je.id = jel.journal_entry_id
+    WHERE je.company_id = p_company_id
+      AND je.status = 'posted'
+      AND je.entry_date < p_period_start
+      AND je.source_type = 'opening_balance'
+      AND substr(jel.account_number, 1, 1) BETWEEN '1' AND '2'
+  ),
+  earliest_ib AS (
+    SELECT account_number, debit_amount, credit_amount, entry_date
+    FROM ib_lines_ranked
+    WHERE rn = 1
+  ),
+  non_ib_lines AS (
+    -- Non-IB, non-storno posted lines. Excluding source_type = 'storno'
+    -- pairs with the status = 'posted' filter on reversed originals so a
+    -- cancelled entry contributes zero on both sides. Regular posted
+    -- transactions contribute their amounts.
+    SELECT
+      jel.account_number,
+      jel.debit_amount,
+      jel.credit_amount,
+      je.entry_date
+    FROM journal_entry_lines jel
+    JOIN journal_entries je ON je.id = jel.journal_entry_id
+    WHERE je.company_id = p_company_id
+      AND je.status = 'posted'
+      AND je.entry_date < p_period_start
+      AND je.source_type NOT IN ('opening_balance', 'storno')
+      AND substr(jel.account_number, 1, 1) BETWEEN '1' AND '2'
+  ),
+  effective_ib AS (
+    -- Keep earliest IB for an account only if no non-IB activity predates it.
+    -- A later-year IB for an account with prior-year transactions is just a
+    -- restatement of the prior UB — already summed in non_ib_lines.
+    SELECT eib.account_number, eib.debit_amount, eib.credit_amount
+    FROM earliest_ib eib
+    WHERE NOT EXISTS (
+      SELECT 1
+      FROM non_ib_lines nil
+      WHERE nil.account_number = eib.account_number
+        AND nil.entry_date < eib.entry_date
+    )
+  ),
+  all_lines AS (
+    SELECT account_number, debit_amount, credit_amount FROM effective_ib
+    UNION ALL
+    SELECT account_number, debit_amount, credit_amount
+    FROM non_ib_lines
+  )
+  SELECT
+    account_number,
+    SUM(debit_amount)::numeric  AS debit,
+    SUM(credit_amount)::numeric AS credit
+  FROM all_lines
+  GROUP BY account_number;
+$$;
+
+GRANT EXECUTE ON FUNCTION compute_prior_opening_balances(uuid, date) TO authenticated;
+
+NOTIFY pgrst, 'reload schema';