diff --git a/packages/0x.js/src/types.ts b/packages/0x.js/src/types.ts
index 11683378f8..da19713874 100644
--- a/packages/0x.js/src/types.ts
+++ b/packages/0x.js/src/types.ts
@@ -490,6 +490,7 @@ export interface OrderRelevantState {
     filledTakerTokenAmount: BigNumber;
     canceledTakerTokenAmount: BigNumber;
     remainingFillableMakerTokenAmount: BigNumber;
+    remainingFillableTakerTokenAmount: BigNumber;
 }
 
 export interface OrderStateValid {