diff --git a/Sources/Misc/Deprecations.swift b/Sources/Misc/Deprecations.swift
index d1bfb7e77d..8447d2108f 100644
--- a/Sources/Misc/Deprecations.swift
+++ b/Sources/Misc/Deprecations.swift
@@ -403,7 +403,7 @@ extension CustomerInfo {
             self.quantity = 1
         }
 
-        func finish(_ wrapper: PaymentQueueWrapperType, completion: @escaping () -> Void) {
+        func finish(_ wrapper: PaymentQueueWrapperType, completion: @escaping @Sendable () -> Void) {
             completion()
         }
 
diff --git a/Sources/Purchasing/StoreKitAbstractions/SK1StoreTransaction.swift b/Sources/Purchasing/StoreKitAbstractions/SK1StoreTransaction.swift
index 60ecbf4b77..952bc99065 100644
--- a/Sources/Purchasing/StoreKitAbstractions/SK1StoreTransaction.swift
+++ b/Sources/Purchasing/StoreKitAbstractions/SK1StoreTransaction.swift
@@ -31,7 +31,7 @@ internal struct SK1StoreTransaction: StoreTransactionType {
     let transactionIdentifier: String
     let quantity: Int
 
-    func finish(_ wrapper: PaymentQueueWrapperType, completion: @escaping () -> Void) {
+    func finish(_ wrapper: PaymentQueueWrapperType, completion: @escaping @Sendable () -> Void) {
         wrapper.finishTransaction(self.underlyingSK1Transaction)
         completion()
     }
diff --git a/Sources/Purchasing/StoreKitAbstractions/SK2StoreTransaction.swift b/Sources/Purchasing/StoreKitAbstractions/SK2StoreTransaction.swift
index 209a9927ea..b3d847884f 100644
--- a/Sources/Purchasing/StoreKitAbstractions/SK2StoreTransaction.swift
+++ b/Sources/Purchasing/StoreKitAbstractions/SK2StoreTransaction.swift
@@ -32,7 +32,7 @@ internal struct SK2StoreTransaction: StoreTransactionType {
     let transactionIdentifier: String
     let quantity: Int
 
-    func finish(_ wrapper: PaymentQueueWrapperType, completion: @escaping () -> Void) {
+    func finish(_ wrapper: PaymentQueueWrapperType, completion: @escaping @Sendable () -> Void) {
         Async.call(with: completion) {
             await self.underlyingSK2Transaction.finish()
         }