3 files changed, 18 insertions, 11 deletions
diff --git a/packages/order-utils/src/order_state_utils.ts b/packages/order-utils/src/order_state_utils.ts
index dbb65de59..3752fdadb 100644
--- a/packages/order-utils/src/order_state_utils.ts
+++ b/packages/order-utils/src/order_state_utils.ts
@@ -14,6 +14,7 @@ import { AbstractOrderFilledCancelledFetcher } from './abstract/abstract_order_f
 import { constants } from './constants';
 import { orderHashUtils } from './order_hash';
 import { RemainingFillableCalculator } from './remaining_fillable_calculator';
+import { utils } from './utils';
 
 interface SidedOrderRelevantState {
     isMakerSide: boolean;
@@ -161,7 +162,13 @@ export class OrderStateUtils {
             signedOrder,
             signedOrder.takerAddress,
         );
-        const remainingFillableTakerAssetAmountGivenMakersStatus = orderRelevantMakerState.remainingFillableAssetAmount;
+        const remainingFillableTakerAssetAmountGivenMakersStatus = signedOrder.makerAssetAmount.eq(0)
+            ? new BigNumber(0)
+            : utils.getPartialAmount(
+                  orderRelevantMakerState.remainingFillableAssetAmount,
+                  signedOrder.makerAssetAmount,
+                  signedOrder.takerAssetAmount,
+              );
 
         // Get max fillable amount for an order, considering the takers ability to fill
         isMaker = false;
diff --git a/packages/order-utils/src/order_validation_utils.ts b/packages/order-utils/src/order_validation_utils.ts
index fb96502f2..da5b37456 100644
--- a/packages/order-utils/src/order_validation_utils.ts
+++ b/packages/order-utils/src/order_validation_utils.ts
@@ -54,7 +54,7 @@ export class OrderValidationUtils {
         senderAddress: string,
         zrxAssetData: string,
     ): Promise<void> {
-        const fillMakerTokenAmount = OrderValidationUtils._getPartialAmount(
+        const fillMakerTokenAmount = utils.getPartialAmount(
             fillTakerAssetAmount,
             signedOrder.takerAssetAmount,
             signedOrder.makerAssetAmount,
@@ -75,7 +75,7 @@ export class OrderValidationUtils {
             TradeSide.Taker,
             TransferType.Trade,
         );
-        const makerFeeAmount = OrderValidationUtils._getPartialAmount(
+        const makerFeeAmount = utils.getPartialAmount(
             fillTakerAssetAmount,
             signedOrder.takerAssetAmount,
             signedOrder.makerFee,
@@ -88,7 +88,7 @@ export class OrderValidationUtils {
             TradeSide.Maker,
             TransferType.Fee,
         );
-        const takerFeeAmount = OrderValidationUtils._getPartialAmount(
+        const takerFeeAmount = utils.getPartialAmount(
             fillTakerAssetAmount,
             signedOrder.takerAssetAmount,
             signedOrder.takerFee,
@@ -116,13 +116,6 @@ export class OrderValidationUtils {
             throw new Error(ExchangeContractErrs.OrderFillExpired);
         }
     }
-    private static _getPartialAmount(numerator: BigNumber, denominator: BigNumber, target: BigNumber): BigNumber {
-        const fillMakerTokenAmount = numerator
-            .mul(target)
-            .div(denominator)
-            .round(0);
-        return fillMakerTokenAmount;
-    }
     constructor(orderFilledCancelledFetcher: AbstractOrderFilledCancelledFetcher) {
         this._orderFilledCancelledFetcher = orderFilledCancelledFetcher;
     }
diff --git a/packages/order-utils/src/utils.ts b/packages/order-utils/src/utils.ts
index 6149316f6..7aaaf0609 100644
--- a/packages/order-utils/src/utils.ts
+++ b/packages/order-utils/src/utils.ts
@@ -12,4 +12,11 @@ export const utils = {
         const milisecondsInSecond = 1000;
         return new BigNumber(Date.now() / milisecondsInSecond).round();
     },
+    getPartialAmount(numerator: BigNumber, denominator: BigNumber, target: BigNumber): BigNumber {
+        const fillMakerTokenAmount = numerator
+            .mul(target)
+            .div(denominator)
+            .round(0);
+        return fillMakerTokenAmount;
+    },
 };