diff --git a/include/xrpl/protocol/STEitherAmount.h b/include/xrpl/protocol/STEitherAmount.h
index 890270c6ae0..57812221fd7 100644
--- a/include/xrpl/protocol/STEitherAmount.h
+++ b/include/xrpl/protocol/STEitherAmount.h
@@ -186,7 +186,7 @@ operator==(STEitherAmount const& lhs, STEitherAmount const& rhs)
 inline bool
 operator!=(STEitherAmount const& lhs, STEitherAmount const& rhs)
 {
-    return !(lhs == rhs);
+    return !operator==(lhs, rhs);
 }
 
 template <ValidAssetType T1, ValidAssetType T2>
diff --git a/include/xrpl/protocol/STMPTAmount.h b/include/xrpl/protocol/STMPTAmount.h
index eb87ccff11b..347234ab101 100644
--- a/include/xrpl/protocol/STMPTAmount.h
+++ b/include/xrpl/protocol/STMPTAmount.h
@@ -93,23 +93,23 @@ class STMPTAmount final : public MPTAmount,
     int
     signum() const noexcept;
 
-    friend bool
-    operator==(STMPTAmount const& lhs, STMPTAmount const& rhs);
+    bool
+    operator==(STMPTAmount const& rhs);
 
-    friend bool
-    operator!=(STMPTAmount const& lhs, STMPTAmount const& rhs);
+    bool
+    operator!=(STMPTAmount const& rhs);
 };
 
 inline bool
-operator==(STMPTAmount const& lhs, STMPTAmount const& rhs)
+STMPTAmount::operator==(STMPTAmount const& rhs)
 {
-    return lhs.value_ == rhs.value_ && lhs.issue_ == rhs.issue_;
+    return value_ == rhs.value_ && issue_ == rhs.issue_;
 }
 
 inline bool
-operator!=(STMPTAmount const& lhs, STMPTAmount const& rhs)
+STMPTAmount::operator!=(STMPTAmount const& rhs)
 {
-    return !(lhs == rhs);
+    return !operator==(rhs);
 }
 
 STMPTAmount