diff --git a/app/api/invoices/[id]/convert/route.ts b/app/api/invoices/[id]/convert/route.ts
index d5b4da30..352dfb70 100644
--- a/app/api/invoices/[id]/convert/route.ts
+++ b/app/api/invoices/[id]/convert/route.ts
@@ -56,7 +56,7 @@ export async function POST(
 
   // Generate real invoice number
   const { data: invoiceNumber } = await supabase.rpc('generate_invoice_number', {
-    p_user_id: user.id,
+    p_company_id: companyId,
   })
 
   // Create the real invoice
diff --git a/app/api/invoices/route.ts b/app/api/invoices/route.ts
index 5a24ed15..8e2512e6 100644
--- a/app/api/invoices/route.ts
+++ b/app/api/invoices/route.ts
@@ -166,12 +166,12 @@ export async function POST(request: Request) {
   let invoiceNumber: string
   if (documentType === 'delivery_note') {
     const { data: dnNumber } = await supabase.rpc('generate_delivery_note_number', {
-      p_user_id: user.id,
+      p_company_id: companyId,
     })
     invoiceNumber = dnNumber
   } else {
     const { data: baseNumber } = await supabase.rpc('generate_invoice_number', {
-      p_user_id: user.id,
+      p_company_id: companyId,
     })
     invoiceNumber = documentType === 'proforma'
       ? `PF-${baseNumber}`
diff --git a/app/api/pending-operations/[id]/commit/route.ts b/app/api/pending-operations/[id]/commit/route.ts
index 32fbeee8..1ada2794 100644
--- a/app/api/pending-operations/[id]/commit/route.ts
+++ b/app/api/pending-operations/[id]/commit/route.ts
@@ -340,7 +340,7 @@ async function commitCreateInvoice(
 
   // Generate invoice number
   const { data: invoiceNumber } = await supabase.rpc('generate_invoice_number', {
-    p_user_id: userId,
+    p_company_id: companyId,
   })
 
   // Create invoice
diff --git a/app/api/sandbox/seed/route.ts b/app/api/sandbox/seed/route.ts
index e643c923..cab84bdf 100644
--- a/app/api/sandbox/seed/route.ts
+++ b/app/api/sandbox/seed/route.ts
@@ -73,7 +73,7 @@ export async function POST() {
 
     // 3. Seed chart of accounts via RPC
     const { error: coaError } = await supabase.rpc('seed_chart_of_accounts', {
-      p_user_id: userId,
+      p_company_id: companyId,
       p_entity_type: 'enskild_firma',
     })
     if (coaError) throw coaError
@@ -294,7 +294,7 @@ export async function POST() {
 
     // 9. Create journal entries (inserted directly, not via engine, to avoid event emission)
     const { data: voucherNum1 } = await supabase.rpc('next_voucher_number', {
-      p_user_id: userId,
+      p_company_id: companyId,
       p_fiscal_period_id: fiscalPeriod.id,
       p_series: 'A',
     })
@@ -320,7 +320,7 @@ export async function POST() {
     if (je1Error) throw je1Error
 
     const { data: voucherNum2 } = await supabase.rpc('next_voucher_number', {
-      p_user_id: userId,
+      p_company_id: companyId,
       p_fiscal_period_id: fiscalPeriod.id,
       p_series: 'A',
     })
diff --git a/app/api/supplier-invoices/[id]/credit/route.ts b/app/api/supplier-invoices/[id]/credit/route.ts
index bcff6750..4ac2e811 100644
--- a/app/api/supplier-invoices/[id]/credit/route.ts
+++ b/app/api/supplier-invoices/[id]/credit/route.ts
@@ -44,7 +44,7 @@ export async function POST(
 
   // Get next arrival number
   const { data: arrivalNum } = await supabase
-    .rpc('get_next_arrival_number', { p_user_id: user.id })
+    .rpc('get_next_arrival_number', { p_company_id: companyId })
 
   // Create credit note invoice (negative amounts)
   const { data: creditNote, error: creditError } = await supabase
diff --git a/app/api/supplier-invoices/[id]/mark-paid/route.ts b/app/api/supplier-invoices/[id]/mark-paid/route.ts
index 7915c8e3..73ed2009 100644
--- a/app/api/supplier-invoices/[id]/mark-paid/route.ts
+++ b/app/api/supplier-invoices/[id]/mark-paid/route.ts
@@ -123,6 +123,8 @@ export async function POST(
   const { error: paymentError } = await supabase
     .from('supplier_invoice_payments')
     .insert({
+      user_id: user.id,
+      company_id: companyId,
       supplier_invoice_id: id,
       payment_date: paymentDate,
       amount: paymentAmount,
diff --git a/app/api/supplier-invoices/route.ts b/app/api/supplier-invoices/route.ts
index bbef5930..9c4f4459 100644
--- a/app/api/supplier-invoices/route.ts
+++ b/app/api/supplier-invoices/route.ts
@@ -75,7 +75,7 @@ export async function POST(request: Request) {
 
   // Get next arrival number
   const { data: arrivalNum, error: arrivalError } = await supabase
-    .rpc('get_next_arrival_number', { p_user_id: user.id })
+    .rpc('get_next_arrival_number', { p_company_id: companyId })
 
   if (arrivalError) {
     return NextResponse.json({ error: 'Failed to get arrival number' }, { status: 500 })
diff --git a/extensions/general/ai-categorization/categorizer.ts b/extensions/general/ai-categorization/categorizer.ts
index bef81780..509052fe 100644
--- a/extensions/general/ai-categorization/categorizer.ts
+++ b/extensions/general/ai-categorization/categorizer.ts
@@ -76,6 +76,7 @@ export interface CategorizationSuggestion {
 export interface TrackingContext {
   supabase: SupabaseClient
   userId: string
+  companyId?: string
 }
 
 export interface CategorizationProvider {
@@ -336,7 +337,7 @@ ${transactionList}`
             inputTokens: message.usage.input_tokens,
             outputTokens: message.usage.output_tokens,
             model: this.model,
-          })
+          }, tracking.companyId)
         }
 
         // Extract tool_use block from response
diff --git a/extensions/general/ai-chat/chatbot/chain.ts b/extensions/general/ai-chat/chatbot/chain.ts
index 6772d672..e6ae608d 100644
--- a/extensions/general/ai-chat/chatbot/chain.ts
+++ b/extensions/general/ai-chat/chatbot/chain.ts
@@ -36,7 +36,7 @@ export interface ChatResult {
 export async function generateChatResponse(
   userMessage: string,
   conversationHistory: ChatMessage[],
-  tracking?: { supabase: SupabaseClient; userId: string }
+  tracking?: { supabase: SupabaseClient; userId: string; companyId?: string }
 ): Promise<ChatResult> {
   // 1. Retrieve relevant documents
   const relevantDocs = await retrieveRelevantDocuments(userMessage)
@@ -81,7 +81,7 @@ export async function generateChatResponse(
       inputTokens: response.usage_metadata.input_tokens ?? 0,
       outputTokens: response.usage_metadata.output_tokens ?? 0,
       model: CHATBOT_CONFIG.model,
-    })
+    }, tracking.companyId)
   }
 
   // 7. Extract content and sources
diff --git a/extensions/general/arcim-migration/lib/migration-orchestrator.ts b/extensions/general/arcim-migration/lib/migration-orchestrator.ts
index d158fd04..7f5a05e1 100644
--- a/extensions/general/arcim-migration/lib/migration-orchestrator.ts
+++ b/extensions/general/arcim-migration/lib/migration-orchestrator.ts
@@ -403,7 +403,7 @@ export async function executeMigration(options: MigrationOptions): Promise<Migra
 
           // Get next arrival number (ankomstnummer) — required NOT NULL column
           const { data: arrivalNum, error: arrivalError } = await supabase
-            .rpc('get_next_arrival_number', { p_user_id: userId })
+            .rpc('get_next_arrival_number', { p_company_id: userId })
 
           if (arrivalError || arrivalNum == null) {
             console.error(`[migration] Supplier invoice ${inv.invoiceNumber} skipped — could not get arrival number:`, arrivalError?.message)
diff --git a/extensions/general/invoice-inbox/api-routes.ts b/extensions/general/invoice-inbox/api-routes.ts
index 30f24011..812b39e4 100644
--- a/extensions/general/invoice-inbox/api-routes.ts
+++ b/extensions/general/invoice-inbox/api-routes.ts
@@ -166,6 +166,7 @@ async function uploadAndCreateInboxItem(
     .from('invoice_inbox_items')
     .insert({
       user_id: userId,
+      company_id: companyId,
       status: 'processing',
       source: 'upload',
       document_id: document.id,
@@ -818,7 +819,7 @@ async function handleConfirmInboxItem(
 
     // Get next arrival number
     const { data: arrivalNum, error: arrivalError } = await supabase
-      .rpc('get_next_arrival_number', { p_user_id: userId })
+      .rpc('get_next_arrival_number', { p_company_id: companyId })
 
     if (arrivalError) {
       console.error('[invoice-inbox] Confirm: arrival number error:', arrivalError)
diff --git a/lib/ai/usage-tracker.ts b/lib/ai/usage-tracker.ts
index 9d5c464c..8ad9eccd 100644
--- a/lib/ai/usage-tracker.ts
+++ b/lib/ai/usage-tracker.ts
@@ -16,12 +16,14 @@ export function trackTokenUsage(
   supabase: SupabaseClient,
   userId: string,
   extensionId: string,
-  usage: TokenUsage
+  usage: TokenUsage,
+  companyId?: string
 ): void {
   supabase
     .from('ai_usage_tracking')
     .insert({
       user_id: userId,
+      company_id: companyId,
       extension_id: extensionId,
       model: usage.model,
       input_tokens: usage.inputTokens,
diff --git a/lib/core/documents/document-service.ts b/lib/core/documents/document-service.ts
index 754224e9..7f907262 100644
--- a/lib/core/documents/document-service.ts
+++ b/lib/core/documents/document-service.ts
@@ -91,6 +91,7 @@ export async function uploadDocument(
     .from('document_attachments')
     .insert({
       user_id: userId,
+      company_id: companyId,
       storage_path: storagePath,
       file_name: file.name,
       file_size_bytes: file.buffer.byteLength,
diff --git a/lib/invoices/reminder-processor.ts b/lib/invoices/reminder-processor.ts
index f6eeaab1..b09c386c 100644
--- a/lib/invoices/reminder-processor.ts
+++ b/lib/invoices/reminder-processor.ts
@@ -210,6 +210,7 @@ export async function processOverdueReminders(): Promise<ProcessRemindersResult>
       .insert({
         invoice_id: invoice.id,
         user_id: invoice.user_id,
+        company_id: invoice.company_id,
         reminder_level: reminderLevel,
         email_to: customer.email
       })