diff --git a/src/lib/db/repos/usageRepo.js b/src/lib/db/repos/usageRepo.js
index 2f86ff14..41199937 100644
--- a/src/lib/db/repos/usageRepo.js
+++ b/src/lib/db/repos/usageRepo.js
@@ -634,7 +634,7 @@ export async function getUsageStats(period = "all") {
         const keyInfo = apiKeyMap[r.apiKey];
         const keyName = keyInfo?.name || r.apiKey.slice(0, 8) + "...";
         const apiKeyMasked = maskApiKey(r.apiKey);
-        const akKey = `${apiKeyMasked}|${r.model}|${r.provider || "unknown"}`;
+        const akKey = `${r.apiKey}|${r.model}|${r.provider || "unknown"}`;
         if (!stats.byApiKey[akKey]) {
           stats.byApiKey[akKey] = { requests: 0, promptTokens: 0, completionTokens: 0, cachedTokens: 0, cost: 0, rawModel: r.model, provider: providerDisplayName, apiKeyMasked, keyName, apiKeyKey: apiKeyMasked, lastUsed: r.timestamp };
         }
diff --git a/tests/unit/usage-api-key-attribution.test.js b/tests/unit/usage-api-key-attribution.test.js
new file mode 100644
index 00000000..049c2898
--- /dev/null
+++ b/tests/unit/usage-api-key-attribution.test.js
@@ -0,0 +1,57 @@
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+import { describe, it, expect, beforeEach, afterEach, vi } from "vitest";
+
+let tempDir;
+let db;
+
+beforeEach(async () => {
+  tempDir = fs.mkdtempSync(path.join(os.tmpdir(), "9router-api-key-"));
+  process.env.DATA_DIR = tempDir;
+  vi.resetModules();
+  db = await import("@/lib/db/index.js");
+  await db.initDb();
+});
+
+afterEach(() => {
+  delete process.env.DATA_DIR;
+});
+
+describe("Usage stats API key attribution", () => {
+  it("keeps API keys with the same masked prefix in separate buckets", async () => {
+    const apiKeyA = "sk-machine-aaaaaa-11111111";
+    const apiKeyB = "sk-machine-bbbbbb-22222222";
+
+    await db.saveRequestUsage({
+      provider: "openai",
+      model: "gpt-4",
+      connectionId: "c1",
+      apiKey: apiKeyA,
+      tokens: { prompt_tokens: 10, completion_tokens: 5 },
+      endpoint: "/v1/chat",
+      status: "ok",
+    });
+
+    await db.saveRequestUsage({
+      provider: "openai",
+      model: "gpt-4",
+      connectionId: "c1",
+      apiKey: apiKeyB,
+      tokens: { prompt_tokens: 20, completion_tokens: 10 },
+      endpoint: "/v1/chat",
+      status: "ok",
+    });
+
+    const stats = await db.getUsageStats("24h");
+    const apiKeyEntries = Object.values(stats.byApiKey);
+
+    expect(apiKeyEntries).toHaveLength(2);
+
+    expect(
+      apiKeyEntries
+        .map((entry) => entry.promptTokens)
+        .sort((a, b) => a - b)
+    ).toEqual([10, 20]);
+  });
+});