diff --git a/src/index.ts b/src/index.ts
index 67a814d4..6a07e404 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -428,7 +428,7 @@ export class ERC725 {
   static encodePermissions(permissions: Permissions): string {
     const result = Object.keys(permissions).reduce((previous, key) => {
       return permissions[key]
-        ? previous + Number(hexToNumber(LSP6_DEFAULT_PERMISSIONS[key]))
+        ? previous | Number(hexToNumber(LSP6_DEFAULT_PERMISSIONS[key]))
         : previous;
     }, 0);