diff --git a/backend/app/demo/seed.py b/backend/app/demo/seed.py
index de1a889..ac559cc 100644
--- a/backend/app/demo/seed.py
+++ b/backend/app/demo/seed.py
@@ -15,6 +15,7 @@ from app.db.models import (
     InvestmentTransaction, ManualCGTDisposal, NetWorthSnapshot, Payslip,
     TaxProfile, Transaction, User,
 )
+from app.services.tax_service import seed_default_rates
 
 DEMO_EMAIL = "demo@mymidas.app"
 DEMO_PASSWORD = "demo123"
@@ -509,6 +510,10 @@ async def seed_demo(db: AsyncSession) -> None:
 
     await db.flush()
 
+    # ── Tax rate configs (2025 + 2026 UK defaults) ────────────────────────
+    await seed_default_rates(db, uid)
+    await db.flush()
+
     # ── Historical net worth snapshots (weekly, Oct 2025 → present) ───────
     # Plausible progression: cash + growing investment portfolio, salary in
     # each month, large purchases (car insurance Oct, Christmas Dec, etc.)