diff --git a/src/app/api/reports/accounts/[id]/entries/route.ts b/src/app/api/reports/accounts/[id]/entries/route.ts
new file mode 100644
index 0000000..9d0fd0d
--- /dev/null
+++ b/src/app/api/reports/accounts/[id]/entries/route.ts
@@ -0,0 +1,52 @@
+/**
+ * GET /api/reports/accounts/[id]/entries
+ *
+ * Drill-down: all POSTED journal entry lines for a specific account.
+ * Shows entry details with running balance.
+ *
+ * Query params:
+ *   startDate? - ISO date string
+ *   endDate?   - ISO date string
+ *
+ * Access: ADMIN, OFFICE_STAFF.
+ */
+import { NextRequest, NextResponse } from "next/server";
+import { withPermission } from "@/lib/middleware/authorize";
+import { withTenantContext } from "@/lib/prisma-tenant";
+import { FinancialReportService } from "@/lib/services/financial-report-service";
+
+export function GET(
+  req: NextRequest,
+  { params }: { params: Promise<{ id: string }> }
+) {
+  return withPermission("read", "Report")(
+    async (innerReq: NextRequest, { user }) => {
+      if (!user.tenantId) {
+        return NextResponse.json(
+          { error: "No tenant context -- super-admins must use the admin API" },
+          { status: 400 }
+        );
+      }
+
+      const { id: accountId } = await params;
+
+      const { searchParams } = new URL(innerReq.url);
+      const startDateParam = searchParams.get("startDate");
+      const endDateParam = searchParams.get("endDate");
+
+      const tenantPrisma = withTenantContext(user.tenantId);
+
+      try {
+        const report = await FinancialReportService.getAccountEntries(tenantPrisma, {
+          accountId,
+          startDate: startDateParam ? new Date(startDateParam) : undefined,
+          endDate: endDateParam ? new Date(endDateParam) : undefined,
+        });
+        return NextResponse.json(report);
+      } catch (err) {
+        const message = err instanceof Error ? err.message : "Failed to get account entries";
+        return NextResponse.json({ error: message }, { status: 400 });
+      }
+    }
+  )(req);
+}
diff --git a/src/app/api/reports/balance-sheet/route.ts b/src/app/api/reports/balance-sheet/route.ts
new file mode 100644
index 0000000..d7a74ab
--- /dev/null
+++ b/src/app/api/reports/balance-sheet/route.ts
@@ -0,0 +1,57 @@
+/**
+ * GET /api/reports/balance-sheet
+ *
+ * Balance Sheet -- assets = liabilities + equity as of a date.
+ * Derived entirely from POSTED journal entry lines.
+ *
+ * Query params:
+ *   asOfDate - ISO date string (required)
+ *
+ * Access: ADMIN only.
+ */
+import { NextRequest, NextResponse } from "next/server";
+import { withPermission } from "@/lib/middleware/authorize";
+import { withTenantContext } from "@/lib/prisma-tenant";
+import { FinancialReportService } from "@/lib/services/financial-report-service";
+
+export const GET = withPermission("read", "Report")(
+  async (req: NextRequest, { user }) => {
+    if (!user.tenantId) {
+      return NextResponse.json(
+        { error: "No tenant context -- super-admins must use the admin API" },
+        { status: 400 }
+      );
+    }
+
+    const { searchParams } = new URL(req.url);
+    const asOfDateParam = searchParams.get("asOfDate");
+
+    if (!asOfDateParam) {
+      return NextResponse.json(
+        { error: "asOfDate query parameter is required" },
+        { status: 400 }
+      );
+    }
+
+    const asOfDate = new Date(asOfDateParam);
+
+    if (isNaN(asOfDate.getTime())) {
+      return NextResponse.json(
+        { error: "asOfDate must be a valid ISO date string" },
+        { status: 400 }
+      );
+    }
+
+    const tenantPrisma = withTenantContext(user.tenantId);
+
+    try {
+      const report = await FinancialReportService.getBalanceSheet(tenantPrisma, {
+        asOfDate,
+      });
+      return NextResponse.json(report);
+    } catch (err) {
+      const message = err instanceof Error ? err.message : "Failed to generate balance sheet";
+      return NextResponse.json({ error: message }, { status: 500 });
+    }
+  }
+);
diff --git a/src/app/api/reports/income-statement/route.ts b/src/app/api/reports/income-statement/route.ts
new file mode 100644
index 0000000..84c4e48
--- /dev/null
+++ b/src/app/api/reports/income-statement/route.ts
@@ -0,0 +1,61 @@
+/**
+ * GET /api/reports/income-statement
+ *
+ * Income Statement -- revenue minus expenses for a date range.
+ * Derived entirely from POSTED journal entry lines.
+ *
+ * Query params:
+ *   startDate - ISO date string (required)
+ *   endDate   - ISO date string (required)
+ *
+ * Access: ADMIN only.
+ */
+import { NextRequest, NextResponse } from "next/server";
+import { withPermission } from "@/lib/middleware/authorize";
+import { withTenantContext } from "@/lib/prisma-tenant";
+import { FinancialReportService } from "@/lib/services/financial-report-service";
+
+export const GET = withPermission("read", "Report")(
+  async (req: NextRequest, { user }) => {
+    if (!user.tenantId) {
+      return NextResponse.json(
+        { error: "No tenant context -- super-admins must use the admin API" },
+        { status: 400 }
+      );
+    }
+
+    const { searchParams } = new URL(req.url);
+    const startDateParam = searchParams.get("startDate");
+    const endDateParam = searchParams.get("endDate");
+
+    if (!startDateParam || !endDateParam) {
+      return NextResponse.json(
+        { error: "startDate and endDate query parameters are required" },
+        { status: 400 }
+      );
+    }
+
+    const startDate = new Date(startDateParam);
+    const endDate = new Date(endDateParam);
+
+    if (isNaN(startDate.getTime()) || isNaN(endDate.getTime())) {
+      return NextResponse.json(
+        { error: "startDate and endDate must be valid ISO date strings" },
+        { status: 400 }
+      );
+    }
+
+    const tenantPrisma = withTenantContext(user.tenantId);
+
+    try {
+      const report = await FinancialReportService.getIncomeStatement(tenantPrisma, {
+        startDate,
+        endDate,
+      });
+      return NextResponse.json(report);
+    } catch (err) {
+      const message = err instanceof Error ? err.message : "Failed to generate income statement";
+      return NextResponse.json({ error: message }, { status: 500 });
+    }
+  }
+);
diff --git a/src/app/api/reports/trial-balance/route.ts b/src/app/api/reports/trial-balance/route.ts
new file mode 100644
index 0000000..070c9d1
--- /dev/null
+++ b/src/app/api/reports/trial-balance/route.ts
@@ -0,0 +1,41 @@
+/**
+ * GET /api/reports/trial-balance
+ *
+ * Trial Balance report -- all account balances, verifies debits = credits.
+ * Derived entirely from POSTED journal entry lines.
+ *
+ * Query params:
+ *   asOfDate? - ISO date string (default: now)
+ *
+ * Access: ADMIN only.
+ */
+import { NextRequest, NextResponse } from "next/server";
+import { withPermission } from "@/lib/middleware/authorize";
+import { withTenantContext } from "@/lib/prisma-tenant";
+import { FinancialReportService } from "@/lib/services/financial-report-service";
+
+export const GET = withPermission("read", "Report")(
+  async (req: NextRequest, { user }) => {
+    if (!user.tenantId) {
+      return NextResponse.json(
+        { error: "No tenant context -- super-admins must use the admin API" },
+        { status: 400 }
+      );
+    }
+
+    const { searchParams } = new URL(req.url);
+    const asOfDateParam = searchParams.get("asOfDate");
+
+    const tenantPrisma = withTenantContext(user.tenantId);
+
+    try {
+      const report = await FinancialReportService.getTrialBalance(tenantPrisma, {
+        asOfDate: asOfDateParam ? new Date(asOfDateParam) : undefined,
+      });
+      return NextResponse.json(report);
+    } catch (err) {
+      const message = err instanceof Error ? err.message : "Failed to generate trial balance";
+      return NextResponse.json({ error: message }, { status: 500 });
+    }
+  }
+);