diff --git a/src/utils.ts b/src/utils.ts
index a23c1c7..eb3547e 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -21,7 +21,7 @@ const FILE_VERSION_READERS = {
   "package.json": (content: string) =>
     JSON.parse(content).packageManager?.split("bun@")?.[1],
   ".tool-versions": (content: string) =>
-    content.match(/^bun\s(?<version>.*?)$/m)?.groups?.version,
+    content.match(/^bun\s?(?<version>.*?)$/m)?.groups?.version,
   ".bumrc": (content: string) => content,
 };