diff --git a/functions/src/place-bet.ts b/functions/src/place-bet.ts
index 11ae425d..497f5dd1 100644
--- a/functions/src/place-bet.ts
+++ b/functions/src/place-bet.ts
@@ -42,6 +42,10 @@ export const placeBet = functions.runWith({ minInstances: 1 }).https.onCall(
         return { status: 'error', message: 'Invalid contract' }
       const contract = contractSnap.data() as Contract
 
+      const { closeTime } = contract
+      if (closeTime && Date.now() > closeTime)
+        return { status: 'error', message: 'Trading is closed' }
+
       const newBetDoc = firestore
         .collection(`contracts/${contractId}/bets`)
         .doc()
diff --git a/functions/src/sell-bet.ts b/functions/src/sell-bet.ts
index 3d37d3c3..e68df796 100644
--- a/functions/src/sell-bet.ts
+++ b/functions/src/sell-bet.ts
@@ -33,6 +33,10 @@ export const sellBet = functions.runWith({ minInstances: 1 }).https.onCall(
         return { status: 'error', message: 'Invalid contract' }
       const contract = contractSnap.data() as Contract
 
+      const { closeTime } = contract
+      if (closeTime && Date.now() > closeTime)
+        return { status: 'error', message: 'Trading is closed' }
+
       const betDoc = firestore.doc(`contracts/${contractId}/bets/${betId}`)
       const betSnap = await transaction.get(betDoc)
       if (!betSnap.exists) return { status: 'error', message: 'Invalid bet' }
diff --git a/web/components/bets-list.tsx b/web/components/bets-list.tsx
index b622c58e..4cc376f6 100644
--- a/web/components/bets-list.tsx
+++ b/web/components/bets-list.tsx
@@ -308,7 +308,8 @@ function BetRow(props: { bet: Bet; contract: Contract; sale?: Bet }) {
     shares,
     isSold,
   } = bet
-  const { isResolved } = contract
+  const { isResolved, closeTime } = contract
+  const isClosed = closeTime && Date.now() > closeTime
 
   return (
     <tr>
@@ -333,7 +334,7 @@ function BetRow(props: { bet: Bet; contract: Contract; sale?: Bet }) {
         )}
       </td>
 
-      {!isResolved && !isSold && (
+      {!isResolved && !isClosed && !isSold && (
         <td className="text-neutral">
           <SellButton contract={contract} bet={bet} />
         </td>