diff --git a/include/xrpl/protocol/STMPTAmount.h b/include/xrpl/protocol/STMPTAmount.h
index 347234ab101..87ddd96e856 100644
--- a/include/xrpl/protocol/STMPTAmount.h
+++ b/include/xrpl/protocol/STMPTAmount.h
@@ -94,20 +94,20 @@ class STMPTAmount final : public MPTAmount,
     signum() const noexcept;
 
     bool
-    operator==(STMPTAmount const& rhs);
+    operator==(STMPTAmount const& rhs) const;
 
     bool
-    operator!=(STMPTAmount const& rhs);
+    operator!=(STMPTAmount const& rhs) const;
 };
 
 inline bool
-STMPTAmount::operator==(STMPTAmount const& rhs)
+STMPTAmount::operator==(STMPTAmount const& rhs) const
 {
     return value_ == rhs.value_ && issue_ == rhs.issue_;
 }
 
 inline bool
-STMPTAmount::operator!=(STMPTAmount const& rhs)
+STMPTAmount::operator!=(STMPTAmount const& rhs) const
 {
     return !operator==(rhs);
 }
diff --git a/src/libxrpl/protocol/STMPTAmount.cpp b/src/libxrpl/protocol/STMPTAmount.cpp
index b1c5a782c66..f2c671862c8 100644
--- a/src/libxrpl/protocol/STMPTAmount.cpp
+++ b/src/libxrpl/protocol/STMPTAmount.cpp
@@ -108,7 +108,7 @@ bool
 STMPTAmount::isEquivalent(const STBase& t) const
 {
     const STMPTAmount* v = dynamic_cast<const STMPTAmount*>(&t);
-    return v && (*v == *this);
+    return v && operator == (*v);
 }
 
 bool