diff --git a/modules/concertBidAdapter.js b/modules/concertBidAdapter.js
index fc6fc23c26d..620e77a5a08 100644
--- a/modules/concertBidAdapter.js
+++ b/modules/concertBidAdapter.js
@@ -34,6 +34,9 @@ export const spec = {
   buildRequests: function(validBidRequests, bidderRequest) {
     logMessage(validBidRequests);
     logMessage(bidderRequest);
+
+    const eids = [];
+
     let payload = {
       meta: {
         prebidVersion: '$prebid.version$',
@@ -49,6 +52,10 @@ export const spec = {
     };
 
     payload.slots = validBidRequests.map(bidRequest => {
+      collectEid(eids, bidRequest);
+      const adUnitElement = document.getElementById(bidRequest.adUnitCode)
+      const coordinates = getOffset(adUnitElement)
+
       let slot = {
         name: bidRequest.adUnitCode,
         bidId: bidRequest.bidId,
@@ -59,12 +66,15 @@ export const spec = {
         adSlot: bidRequest.params.slot || bidRequest.adUnitCode,
         placementId: bidRequest.params.placementId || '',
         site: bidRequest.params.site || bidderRequest.refererInfo.page,
-        ref: bidderRequest.refererInfo.ref
-      };
+        ref: bidderRequest.refererInfo.ref,
+        offsetCoordinates: { x: coordinates?.left, y: coordinates?.top }
+      }
 
       return slot;
     });
 
+    payload.meta.eids = eids.filter(Boolean);
+
     logMessage(payload);
 
     return {
@@ -216,3 +226,35 @@ function consentAllowsPpid(bidderRequest) {
 
   return (uspConsent || gdprConsent);
 }
+
+function collectEid(eids, bid) {
+  if (bid.userId) {
+    const eid = getUserId(bid.userId.uid2 && bid.userId.uid2.id, 'uidapi.com', undefined, 3)
+    eids.push(eid)
+  }
+}
+
+function getUserId(id, source, uidExt, atype) {
+  if (id) {
+    const uid = { id, atype };
+
+    if (uidExt) {
+      uid.ext = uidExt;
+    }
+
+    return {
+      source,
+      uids: [ uid ]
+    };
+  }
+}
+
+function getOffset(el) {
+  if (el) {
+    const rect = el.getBoundingClientRect();
+    return {
+      left: rect.left + window.scrollX,
+      top: rect.top + window.scrollY
+    };
+  }
+}
diff --git a/test/spec/modules/concertBidAdapter_spec.js b/test/spec/modules/concertBidAdapter_spec.js
index 2f9eda0ca7c..10ea997b304 100644
--- a/test/spec/modules/concertBidAdapter_spec.js
+++ b/test/spec/modules/concertBidAdapter_spec.js
@@ -7,11 +7,33 @@ describe('ConcertAdapter', function () {
   let bidRequests;
   let bidRequest;
   let bidResponse;
+  let element;
+  let sandbox;
 
   afterEach(function () {
     $$PREBID_GLOBAL$$.bidderSettings = {};
+    sandbox.restore();
   });
+
   beforeEach(function () {
+    element = {
+      x: 0,
+      y: 0,
+      width: 0,
+      height: 0,
+      getBoundingClientRect: () => {
+        return {
+          width: element.width,
+          height: element.height,
+
+          left: element.x,
+          top: element.y,
+          right: element.x + element.width,
+          bottom: element.y + element.height
+        };
+      }
+    };
+
     $$PREBID_GLOBAL$$.bidderSettings = {
       concert: {
         storageAllowed: true
@@ -56,6 +78,9 @@ describe('ConcertAdapter', function () {
         ]
       }
     }
+
+    sandbox = sinon.sandbox.create();
+    sandbox.stub(document, 'getElementById').withArgs('desktop_leaderboard_variable').returns(element)
   });
 
   describe('spec.isBidRequestValid', function() {
@@ -119,6 +144,37 @@ describe('ConcertAdapter', function () {
 
       expect(payload.meta.uid).to.equal('foo');
     });
+
+    it('should add uid2 to eids list if available', function() {
+      bidRequests[0].userId = { uid2: { id: 'uid123' } }
+
+      const request = spec.buildRequests(bidRequests, bidRequest);
+      const payload = JSON.parse(request.data);
+      const meta = payload.meta
+
+      expect(meta.eids.length).to.equal(1);
+      expect(meta.eids[0].uids[0].id).to.equal('uid123')
+      expect(meta.eids[0].uids[0].atype).to.equal(3)
+    })
+
+    it('should return empty eids list if none are available', function() {
+      bidRequests[0].userId = { testId: { id: 'uid123' } }
+      const request = spec.buildRequests(bidRequests, bidRequest);
+      const payload = JSON.parse(request.data);
+      const meta = payload.meta
+
+      expect(meta.eids.length).to.equal(0);
+    });
+
+    it('should return x/y offset coordiantes when element is present', function() {
+      Object.assign(element, { x: 100, y: 0, width: 400, height: 400 })
+      const request = spec.buildRequests(bidRequests, bidRequest);
+      const payload = JSON.parse(request.data);
+      const slot = payload.slots[0];
+
+      expect(slot.offsetCoordinates.x).to.equal(100)
+      expect(slot.offsetCoordinates.y).to.equal(0)
+    })
   });
 
   describe('spec.interpretResponse', function() {