diff --git a/apps/server/src/usage/usageAggregation.test.ts b/apps/server/src/usage/usageAggregation.test.ts
index e7af899653aec..3819903606be2 100644
--- a/apps/server/src/usage/usageAggregation.test.ts
+++ b/apps/server/src/usage/usageAggregation.test.ts
@@ -292,20 +292,24 @@ describe("UsageAggregator", () => {
 
 describe("resolveModelAliases", () => {
   it("follows chains to the final model and drops chains that enter a loop", () => {
-    expect(
-      resolveModelAliases({
+    expect([
+      ...resolveModelAliases({
         "preview[1m]": "preview",
         preview: "example-model",
+        shared: "preview",
+        intoLoop: "loop",
         loop: "back",
         back: "loop",
-        intoLoop: "loop",
+        laterIntoLoop: "back",
+        deepIntoLoop: "intoLoop",
         self: "self",
+        validAfterLoops: "shared",
       }),
-    ).toEqual(
-      new Map([
-        ["preview[1m]", "example-model"],
-        ["preview", "example-model"],
-      ]),
-    );
+    ]).toEqual([
+      ["preview[1m]", "example-model"],
+      ["preview", "example-model"],
+      ["shared", "example-model"],
+      ["validAfterLoops", "example-model"],
+    ]);
   });
 });
diff --git a/apps/server/src/usage/usageAggregation.ts b/apps/server/src/usage/usageAggregation.ts
index 649133b00b67b..ce7a78a99d9c1 100644
--- a/apps/server/src/usage/usageAggregation.ts
+++ b/apps/server/src/usage/usageAggregation.ts
@@ -79,15 +79,26 @@ export interface AggregateOptions {
 export function resolveModelAliases(
   aliases: Readonly<Record<string, string>>,
 ): ReadonlyMap<string, string> {
-  const resolved = new Map<string, string>();
-  for (const model of Object.keys(aliases)) {
-    const seen = new Set([model]);
-    let target = aliases[model]!;
-    while (Object.hasOwn(aliases, target) && !seen.has(target)) {
-      seen.add(target);
+  const models = Object.keys(aliases);
+  const memo = new Map<string, string | null>();
+  for (const model of models) {
+    if (memo.has(model)) continue;
+    const path: string[] = [];
+    let target = model;
+    while (Object.hasOwn(aliases, target) && !memo.has(target)) {
+      path.push(target);
+      // Null marks both the active walk and paths that end in a cycle.
+      memo.set(target, null);
       target = aliases[target]!;
     }
-    if (!Object.hasOwn(aliases, target)) resolved.set(model, target);
+    const terminal = Object.hasOwn(aliases, target) ? (memo.get(target) ?? null) : target;
+    for (const alias of path) memo.set(alias, terminal);
+  }
+
+  const resolved = new Map<string, string>();
+  for (const model of models) {
+    const target = memo.get(model);
+    if (target !== null && target !== undefined) resolved.set(model, target);
   }
   return resolved;
 }