diff --git a/include/nlohmann/detail/output/binary_writer.hpp b/include/nlohmann/detail/output/binary_writer.hpp
index c682e72dc..864038078 100644
--- a/include/nlohmann/detail/output/binary_writer.hpp
+++ b/include/nlohmann/detail/output/binary_writer.hpp
@@ -901,7 +901,9 @@ class binary_writer
                         return ubjson_prefix(v, use_bjdata) == first_prefix;
                     });
 
-                    if (same_prefix && !(use_bjdata && std::string("[{SHTFNZ").find(static_cast<char>(first_prefix)) != std::string::npos))
+                    std::vector<CharType> bjdx = {'[', '{', 'S', 'H', 'T', 'F', 'N', 'Z'}; // excluded markers in bjdata optimized type
+
+                    if (same_prefix && !(use_bjdata && std::find(bjdx.begin(), bjdx.end(), first_prefix) != bjdx.end()))
                     {
                         prefix_required = false;
                         oa->write_character(to_char_type('$'));
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 974653623..2ebceca74 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -14800,7 +14800,9 @@ class binary_writer
                         return ubjson_prefix(v, use_bjdata) == first_prefix;
                     });
 
-                    if (same_prefix && !(use_bjdata && std::string("[{SHTFNZ").find(static_cast<char>(first_prefix)) != std::string::npos))
+                    std::vector<CharType> bjdx = {'[', '{', 'S', 'H', 'T', 'F', 'N', 'Z'}; // excluded markers in bjdata optimized type
+
+                    if (same_prefix && !(use_bjdata && std::find(bjdx.begin(), bjdx.end(), first_prefix) != bjdx.end()))
                     {
                         prefix_required = false;
                         oa->write_character(to_char_type('$'));