diff --git a/exchange/exchange.go b/exchange/exchange.go
index a6c43763a54..4cf72e25699 100644
--- a/exchange/exchange.go
+++ b/exchange/exchange.go
@@ -119,7 +119,7 @@ func (e *exchange) HoldAuction(ctx context.Context, r AuctionRequest, debugLog *
 	}
 
 	cacheInstructions := getExtCacheInstructions(requestExt)
-	evData := getExtEventsData(&requestExt.Prebid, time.Now(), &r.Account, e.bidderInfo, e.externalURL)
+	evData := getExtEventsData(&requestExt.Prebid, r.StartTime, &r.Account, e.bidderInfo, e.externalURL)
 	targData := getExtTargetData(requestExt, &cacheInstructions)
 	if targData != nil {
 		_, targData.cacheHost, targData.cachePath = e.cache.GetExtCacheData()
diff --git a/exchange/exchange_test.go b/exchange/exchange_test.go
index eb4a92d0aa3..b052d523429 100644
--- a/exchange/exchange_test.go
+++ b/exchange/exchange_test.go
@@ -1398,6 +1398,9 @@ func runSpec(t *testing.T, filename string, spec *exchangeSpec) {
 		},
 		UserSyncs: mockIdFetcher(spec.IncomingRequest.Usersyncs),
 	}
+	if spec.StartTime > 0 {
+		auctionRequest.StartTime = time.Unix(0, spec.StartTime*1e+6)
+	}
 
 	bid, err := ex.HoldAuction(context.Background(), auctionRequest, debugLog)
 	responseTimes := extractResponseTimes(t, filename, bid)
@@ -2541,6 +2544,7 @@ type exchangeSpec struct {
 	AssumeGDPRApplies bool                   `json:"assume_gdpr_applies"`
 	DebugLog          *DebugLog              `json:"debuglog,omitempty"`
 	EventsEnabled     bool                   `json:"events_enabled,omitempty"`
+	StartTime         int64                  `json:"start_time_ms,omitempty"`
 }
 
 type exchangeRequest struct {
diff --git a/exchange/exchangetest/events-account-off-request-on.json b/exchange/exchangetest/events-account-off-request-on.json
index 1cbfff43205..2f6b5f1ac29 100644
--- a/exchange/exchangetest/events-account-off-request-on.json
+++ b/exchange/exchangetest/events-account-off-request-on.json
@@ -1,5 +1,6 @@
 {
   "events_enabled": false,
+  "start_time_ms": 1234567890,
   "incomingRequest": {
     "ortbRequest": {
       "id": "some-request-id",
@@ -127,8 +128,8 @@
                 "prebid": {
                   "type": "video",
                   "events": {
-                    "imp": "http://localhost/event?t=imp&b=contending-bid&a=testaccount&bidder=audienceNetwork&ts=1605928405805",
-                    "win": "http://localhost/event?t=win&b=contending-bid&a=testaccount&bidder=audienceNetwork&ts=1605928405805"
+                    "imp": "http://localhost/event?t=imp&b=contending-bid&a=testaccount&bidder=audienceNetwork&ts=1234567890",
+                    "win": "http://localhost/event?t=win&b=contending-bid&a=testaccount&bidder=audienceNetwork&ts=1234567890"
                   }
                 }
               }
@@ -149,8 +150,8 @@
                 "prebid": {
                   "type": "video",
                   "events": {
-                    "imp": "http://localhost/event?t=imp&b=winning-bid&a=testaccount&bidder=appnexus&ts=1605928405805",
-                    "win": "http://localhost/event?t=win&b=winning-bid&a=testaccount&bidder=appnexus&ts=1605928405805"
+                    "imp": "http://localhost/event?t=imp&b=winning-bid&a=testaccount&bidder=appnexus&ts=1234567890",
+                    "win": "http://localhost/event?t=win&b=winning-bid&a=testaccount&bidder=appnexus&ts=1234567890"
                   }
                 }
               }
@@ -166,8 +167,8 @@
                 "prebid": {
                   "type": "video",
                   "events": {
-                    "imp": "http://localhost/event?t=imp&b=losing-bid&a=testaccount&bidder=appnexus&ts=1605928405805",
-                    "win": "http://localhost/event?t=win&b=losing-bid&a=testaccount&bidder=appnexus&ts=1605928405805"
+                    "imp": "http://localhost/event?t=imp&b=losing-bid&a=testaccount&bidder=appnexus&ts=1234567890",
+                    "win": "http://localhost/event?t=win&b=losing-bid&a=testaccount&bidder=appnexus&ts=1234567890"
                   }
                 }
               }
@@ -183,8 +184,8 @@
                 "prebid": {
                   "type": "video",
                   "events": {
-                    "imp": "http://localhost/event?t=imp&b=other-bid&a=testaccount&bidder=appnexus&ts=1605928405805",
-                    "win": "http://localhost/event?t=win&b=other-bid&a=testaccount&bidder=appnexus&ts=1605928405805"
+                    "imp": "http://localhost/event?t=imp&b=other-bid&a=testaccount&bidder=appnexus&ts=1234567890",
+                    "win": "http://localhost/event?t=win&b=other-bid&a=testaccount&bidder=appnexus&ts=1234567890"
                   }
                 }
               }
@@ -192,6 +193,9 @@
           ]
         }
       ]
+    },
+    "prebid": {
+      "auctiontimestamp": 1234567890
     }
   }
-}
\ No newline at end of file
+}
diff --git a/exchange/exchangetest/events-account-on-request-off.json b/exchange/exchangetest/events-account-on-request-off.json
index 440e34d89bc..23b220c42d1 100644
--- a/exchange/exchangetest/events-account-on-request-off.json
+++ b/exchange/exchangetest/events-account-on-request-off.json
@@ -1,5 +1,6 @@
 {
   "events_enabled": true,
+  "start_time_ms": 1234567890,
   "incomingRequest": {
     "ortbRequest": {
       "id": "some-request-id",
@@ -125,8 +126,8 @@
                 "prebid": {
                   "type": "video",
                   "events": {
-                    "imp": "http://localhost/event?t=imp&b=contending-bid&a=testaccount&bidder=audienceNetwork&ts=1605928405805",
-                    "win": "http://localhost/event?t=win&b=contending-bid&a=testaccount&bidder=audienceNetwork&ts=1605928405805"
+                    "imp": "http://localhost/event?t=imp&b=contending-bid&a=testaccount&bidder=audienceNetwork&ts=1234567890",
+                    "win": "http://localhost/event?t=win&b=contending-bid&a=testaccount&bidder=audienceNetwork&ts=1234567890"
                   }
                 }
               }
@@ -147,8 +148,8 @@
                 "prebid": {
                   "type": "video",
                   "events": {
-                    "imp": "http://localhost/event?t=imp&b=winning-bid&a=testaccount&bidder=appnexus&ts=1605928405805",
-                    "win": "http://localhost/event?t=win&b=winning-bid&a=testaccount&bidder=appnexus&ts=1605928405805"
+                    "imp": "http://localhost/event?t=imp&b=winning-bid&a=testaccount&bidder=appnexus&ts=1234567890",
+                    "win": "http://localhost/event?t=win&b=winning-bid&a=testaccount&bidder=appnexus&ts=1234567890"
                   }
                 }
               }
@@ -164,8 +165,8 @@
                 "prebid": {
                   "type": "video",
                   "events": {
-                    "imp": "http://localhost/event?t=imp&b=losing-bid&a=testaccount&bidder=appnexus&ts=1605928405805",
-                    "win": "http://localhost/event?t=win&b=losing-bid&a=testaccount&bidder=appnexus&ts=1605928405805"
+                    "imp": "http://localhost/event?t=imp&b=losing-bid&a=testaccount&bidder=appnexus&ts=1234567890",
+                    "win": "http://localhost/event?t=win&b=losing-bid&a=testaccount&bidder=appnexus&ts=1234567890"
                   }
                 }
               }
@@ -181,8 +182,8 @@
                 "prebid": {
                   "type": "video",
                   "events": {
-                    "imp": "http://localhost/event?t=imp&b=other-bid&a=testaccount&bidder=appnexus&ts=1605928405805",
-                    "win": "http://localhost/event?t=win&b=other-bid&a=testaccount&bidder=appnexus&ts=1605928405805"
+                    "imp": "http://localhost/event?t=imp&b=other-bid&a=testaccount&bidder=appnexus&ts=1234567890",
+                    "win": "http://localhost/event?t=win&b=other-bid&a=testaccount&bidder=appnexus&ts=1234567890"
                   }
                 }
               }
@@ -190,6 +191,9 @@
           ]
         }
       ]
+    },
+    "prebid": {
+      "auctiontimestamp": 1234567890
     }
   }
 }
\ No newline at end of file