diff --git a/tree/ntuple/v7/inc/ROOT/RNTupleUtil.hxx b/tree/ntuple/v7/inc/ROOT/RNTupleUtil.hxx
index 092dbeeb5473b..052f332fb3fbc 100644
--- a/tree/ntuple/v7/inc/ROOT/RNTupleUtil.hxx
+++ b/tree/ntuple/v7/inc/ROOT/RNTupleUtil.hxx
@@ -154,7 +154,7 @@ struct RNTupleLocator {
 
    /// Simple on-disk locators consisting of a 64-bit offset use variant type `uint64_t`; extended locators have
    /// `fPosition.index()` > 0
-   std::variant<std::uint64_t, std::string, RNTupleLocatorObject64> fPosition;
+   std::variant<std::uint64_t, std::string, RNTupleLocatorObject64> fPosition{};
    std::uint32_t fBytesOnStorage = 0;
    /// For non-disk locators, the value for the _Type_ field. This makes it possible to have different type values even
    /// if the payload structure is identical.