diff --git a/web3.js/module.d.ts b/web3.js/module.d.ts
index 56ef20ab9..3a12dff43 100644
--- a/web3.js/module.d.ts
+++ b/web3.js/module.d.ts
@@ -379,7 +379,7 @@ declare module '@solana/web3.js' {
     instructions: CompiledInstruction[];
 
     constructor(args: MessageArgs);
-    isAccountWritable(account: PublicKey): boolean;
+    isAccountWritable(index: number): boolean;
     serialize(): Buffer;
   }
 
diff --git a/web3.js/module.flow.js b/web3.js/module.flow.js
index 156abcbbc..d06b7646e 100644
--- a/web3.js/module.flow.js
+++ b/web3.js/module.flow.js
@@ -389,7 +389,7 @@ declare module '@solana/web3.js' {
     instructions: CompiledInstruction[];
 
     constructor(args: MessageArgs): Message;
-    isAccountWritable(account: PublicKey): boolean;
+    isAccountWritable(index: number): boolean;
     serialize(): Buffer;
   }