diff --git a/kotlin/reflect/src/main/resources/META-INF/proguard/moshi-kotlin.pro b/kotlin/reflect/src/main/resources/META-INF/proguard/moshi-kotlin.pro
index a72ffdf..1565786 100644
--- a/kotlin/reflect/src/main/resources/META-INF/proguard/moshi-kotlin.pro
+++ b/kotlin/reflect/src/main/resources/META-INF/proguard/moshi-kotlin.pro
@@ -1,3 +1,5 @@
+-keep class kotlin.reflect.jvm.internal.impl.builtins.BuiltInsLoaderImpl
+
 -keepclassmembers class kotlin.Metadata {
     public <methods>;
 }