diff --git a/lib/addons/abTestAssignment.ts b/lib/addons/abTestAssignment.ts
index 8ec63c8..1a4080b 100644
--- a/lib/addons/abTestAssignment.ts
+++ b/lib/addons/abTestAssignment.ts
@@ -134,7 +134,7 @@ export function setupAB(config: SetupABConfig): ABTestSetupResult {
     });
   }
 
-  function setHooks(pbjsInstance: any): void {
+  function registerHooks(pbjsInstance: any): void {
     pbjsInstance.getEvents().forEach((event: any) => {
       if (event.eventType === "auctionEnd") {
         applyToAuctionEvent(event.args);
@@ -143,6 +143,21 @@ export function setupAB(config: SetupABConfig): ABTestSetupResult {
     pbjsInstance.onEvent("auctionEnd", applyToAuctionEvent);
   }
 
+  // Mirrors OptablePrebidAnalytics.hookIntoPrebid: when Prebid.js has not
+  // finished loading yet (`onEvent` is not a function), defer registration onto
+  // its command queue so hooks attach once the real global drains `que`.
+  // This lets callers pass a queue-only stub (`{ que: [] }`) safely instead of
+  // having to queue `setHooks` themselves.
+  function setHooks(pbjsInstance: any): void {
+    if (!pbjsInstance) return;
+    if (typeof pbjsInstance.onEvent !== "function") {
+      pbjsInstance.que = pbjsInstance.que || [];
+      pbjsInstance.que.push(() => registerHooks(pbjsInstance));
+    } else {
+      registerHooks(pbjsInstance);
+    }
+  }
+
   if (pbjs) {
     setHooks(pbjs);
   }