diff --git a/src/prebid.js b/src/prebid.js
index 76681364112..a919f77d7d6 100644
--- a/src/prebid.js
+++ b/src/prebid.js
@@ -154,33 +154,24 @@ function getPresetTargeting() {
   }
 }
 
-function getWinningBids(code) {
-  const getWinningBidForAdUnit = (adUnitCode) => {
-    const adUnits = $$PREBID_GLOBAL$$._bidsReceived
-      .filter(bid => bid.adUnitCode === adUnitCode ? bid : null);
-
-    if (adUnits.length) {
-      return adUnits.reduce(getHighestCpm, {
-        adUnitCode: adUnitCode,
-        cpm: 0,
-        adserverTargeting: {},
-        timeToRespond: 0
-      });
-    }
-  };
-
-  if (code) {
-    return getWinningBidForAdUnit(code);
-  } else {
-    return $$PREBID_GLOBAL$$._bidsReceived
-      .map(bid => bid.adUnitCode)
-      .filter(uniques)
-      .map(getWinningBidForAdUnit);
-  }
+function getWinningBids(adUnitCodes) {
+  return $$PREBID_GLOBAL$$._bidsReceived
+    .filter(adUnitsFilter.bind(this, adUnitCodes))
+    .map(bid => bid.adUnitCode)
+    .filter(uniques)
+    .map(adUnitCode => $$PREBID_GLOBAL$$._bidsReceived
+      .filter(bid => bid.adUnitCode === adUnitCode ? bid : null)
+      .reduce(getHighestCpm,
+        {
+          adUnitCode: adUnitCode,
+          cpm: 0,
+          adserverTargeting: {},
+          timeToRespond: 0
+        }));
 }
 
-function getWinningBidTargeting() {
-  let winners = getWinningBids();
+function getWinningBidTargeting(adUnitCodes) {
+  let winners = getWinningBids(adUnitCodes);
 
   // winning bids with deals need an hb_deal targeting key
   winners
@@ -846,38 +837,16 @@ $$PREBID_GLOBAL$$.buildMasterVideoTagFromAdserverTag = function (adserverTag, op
 };
 
 /**
- * Get winning bids for all ad units on page
- * @return {array} array containing an object for each winning bid
- */
-$$PREBID_GLOBAL$$.getHighestCpmBids = function () {
-  return getWinningBids();
-};
-
-/**
- * Get winning bid for ad unit code
- * @param {string} adUnitCode ad unit code
- * @return {object} winning bid for ad unit code
- */
-$$PREBID_GLOBAL$$.getHighestCpmBidForAdUnit = function (adUnitCode) {
-  if (adUnitCode) {
-    return getWinningBids(adUnitCode);
-  } else {
-    utils.logMessage('getWinningBidForAdUnit requires an adUnitCode');
-  }
-};
-
-/**
- * Get array of highest cpm bids for all adUnits, or highest cpm bid
- * object for the given adUnit
+ * Get array of highest cpm bids for all adUnits or the given adUnit
  * @param {string} optional adUnitCode ad unit code
- * @return {array|object} array or object containing highest cpm bid(s)
+ * @return {array} array containing highest cpm bid object(s)
  */
-$$PREBID_GLOBAL$$.getHighestCpmBid = function (adUnitCode) {
-  if (adUnitCode) {
-    return getWinningBids(adUnitCode);
-  } else {
-    return getWinningBids();
-  }
+$$PREBID_GLOBAL$$.getHighestCpmBids = function (adUnitCode) {
+  const adUnitCodes = adUnitCode && adUnitCode.length ?
+    [adUnitCode] :
+    $$PREBID_GLOBAL$$._adUnitCodes;
+
+  return getWinningBids(adUnitCodes);
 };
 
 processQue();
diff --git a/test/spec/unit/pbjs_api_spec.js b/test/spec/unit/pbjs_api_spec.js
index 1a1d40f46a3..00993da9d34 100644
--- a/test/spec/unit/pbjs_api_spec.js
+++ b/test/spec/unit/pbjs_api_spec.js
@@ -1247,25 +1247,22 @@ describe('Unit: Prebid Module', function () {
   });
 
   describe('getHighestCpm', () => {
-    it('returns an array of winning bids for each adUnit', () => {
-      const highestCpmBids = $$PREBID_GLOBAL$$.getHighestCpmBid();
-
+    it('returns an array of winning bid objects for each adUnit', () => {
+      const highestCpmBids = $$PREBID_GLOBAL$$.getHighestCpmBids();
       expect(highestCpmBids.length).to.equal(2);
       expect(highestCpmBids[0]).to.deep.equal($$PREBID_GLOBAL$$._bidsReceived[1]);
       expect(highestCpmBids[1]).to.deep.equal($$PREBID_GLOBAL$$._bidsReceived[2]);
     });
 
-    it('returns the highest bid for the given adUnitCode', () => {
-      const highestCpmBid = $$PREBID_GLOBAL$$.getHighestCpmBid('/19968336/header-bid-tag-0');
-
-      expect(highestCpmBid).to.be.an('object');
-      expect(highestCpmBid).to.deep.equal($$PREBID_GLOBAL$$._bidsReceived[1]);
+    it('returns an array containing the highest bid object for the given adUnitCode', () => {
+      const highestCpmBids = $$PREBID_GLOBAL$$.getHighestCpmBids('/19968336/header-bid-tag-0');
+      expect(highestCpmBids.length).to.equal(1);
+      expect(highestCpmBids[0]).to.deep.equal($$PREBID_GLOBAL$$._bidsReceived[1]);
     });
 
-    it('returns nothing when the given adUnit is invalid', () => {
-      const shouldBeUndefined = $$PREBID_GLOBAL$$.getHighestCpmBid('Stallone');
-
-      expect(shouldBeUndefined).to.be.undefined;
+    it('returns an empty array when the given adUnit is not found', () => {
+      const highestCpmBids = $$PREBID_GLOBAL$$.getHighestCpmBids('/stallone');
+      expect(highestCpmBids.length).to.equal(0);
     });
   });