diff --git a/functions/src/accept-challenge.ts b/functions/src/accept-challenge.ts
index fa98c8c6..eae6ab55 100644
--- a/functions/src/accept-challenge.ts
+++ b/functions/src/accept-challenge.ts
@@ -47,7 +47,7 @@ export const acceptchallenge = newEndpoint({}, async (req, auth) => {
 
     const creatorDoc = firestore.doc(`users/${challenge.creatorId}`)
     const creatorSnap = await trans.get(creatorDoc)
-    if (!creatorSnap.exists) throw new APIError(400, 'User not found.')
+    if (!creatorSnap.exists) throw new APIError(400, 'Creator not found.')
     const creator = creatorSnap.data() as User
 
     const {
@@ -61,6 +61,9 @@ export const acceptchallenge = newEndpoint({}, async (req, auth) => {
     if (user.balance < acceptorAmount)
       throw new APIError(400, 'Insufficient balance.')
 
+    if (creator.balance < creatorAmount)
+      throw new APIError(400, 'Creator has insufficient balance.')
+
     const contract = anyContract as CPMMBinaryContract
     const shares = (1 / creatorOutcomeProb) * creatorAmount
     const createdTime = Date.now()