diff --git a/packages/bignumber/src.ts/bignumber.ts b/packages/bignumber/src.ts/bignumber.ts
index 807a1ccb3..b57dc35dc 100644
--- a/packages/bignumber/src.ts/bignumber.ts
+++ b/packages/bignumber/src.ts/bignumber.ts
@@ -190,7 +190,7 @@ export class BigNumber implements Hexable {
         return null;
     }
 
-    toBigInt(): BigInt {
+    toBigInt(): bigint {
         try {
             return BigInt(this.toString());
         } catch (e) { }