diff --git a/contracts/Marketplace.sol b/contracts/Marketplace.sol
index 4b1b9f3..eb576d9 100644
--- a/contracts/Marketplace.sol
+++ b/contracts/Marketplace.sol
@@ -25,6 +25,7 @@ contract Marketplace is Collateral {
     require(request.client == msg.sender, "Invalid client address");
     require(requests[id].client == address(0), "Request already exists");
     requests[id] = request;
+    _createLock(id, request.expiry);
     transferFrom(msg.sender, request.maxPrice);
     funds.received += request.maxPrice;
     funds.balance += request.maxPrice;
@@ -40,6 +41,7 @@ contract Marketplace is Collateral {
     require(offers[id].host == address(0), "Offer already exists");
     require(offer.price <= request.maxPrice, "Price too high");
     offers[id] = offer;
+    _lock(msg.sender, offer.requestId);
     emit StorageOffered(id, offer);
   }
 
diff --git a/test/Marketplace.test.js b/test/Marketplace.test.js
index cd804ce..31a38c5 100644
--- a/test/Marketplace.test.js
+++ b/test/Marketplace.test.js
@@ -89,6 +89,11 @@ describe("Marketplace", function () {
         .withArgs(offerId(offer), offerToArray(offer))
     })
 
+    it("locks collateral of host", async function () {
+      await marketplace.offerStorage(offer)
+      await expect(marketplace.withdraw()).to.be.revertedWith("Account locked")
+    })
+
     it("rejects offer with invalid host address", async function () {
       let invalid = { ...offer, host: client.address }
       await expect(marketplace.offerStorage(invalid)).to.be.revertedWith(