diff --git a/include/boost/charconv/detail/ryu/ryu_generic_128.hpp b/include/boost/charconv/detail/ryu/ryu_generic_128.hpp
index a287e25..8592cce 100644
--- a/include/boost/charconv/detail/ryu/ryu_generic_128.hpp
+++ b/include/boost/charconv/detail/ryu/ryu_generic_128.hpp
@@ -599,8 +599,8 @@ static inline struct floating_decimal_128 long_double_to_fd128(long double d) no
 
     #if LDBL_MANT_DIG == 113 // binary128 (e.g. ARM, S390X)
     return generic_binary_to_decimal(bits, 112, 15, true);
-    #elif LLDBL_MANT_DIG == 106 // ibm128 (e.g. PowerPC)
-    return generic_binary_to_decimal(bits, 106, 11, true);
+    #elif LDBL_MANT_DIG == 106 // ibm128 (e.g. PowerPC)
+    return generic_binary_to_decimal(bits, 105, 11, true);
     #endif
 }