diff --git a/cpp/include/raft/util/cudart_utils.hpp b/cpp/include/raft/util/cudart_utils.hpp
--- a/cpp/include/raft/util/cudart_utils.hpp
+++ b/cpp/include/raft/util/cudart_utils.hpp
@@ -21,6 +21,7 @@
 
 #include <rmm/cuda_stream_view.hpp>
 
+#include <cuda_bf16.h>
 #include <cuda_fp16.h>
 #include <cuda_runtime_api.h>
 
@@ -456,4 +457,27 @@ constexpr inline auto upper_bound<half>(
   return static_cast<half>(__half_constexpr{0x7c00u});
 }
 
+/**
+ * This is a hack to allow constexpr definition of `bfloat16` constants.
+ *
+ * Same reasoning as for `half`: CUDA’s `__nv_bfloat16` has no constexpr constructor.
+ */
+struct __bfloat16_constexpr : __nv_bfloat16 {  // NOLINT
+  constexpr explicit inline __bfloat16_constexpr(uint16_t u) : __nv_bfloat16() { __x = u; }
+};
+
+template <>
+constexpr inline auto lower_bound<__nv_bfloat16>() -> __nv_bfloat16
+{
+  // Negative infinity in bfloat16 (sign=1, exp=all ones, mantissa=0)
+  return static_cast<__nv_bfloat16>(__bfloat16_constexpr{0xff80u});
+}
+
+template <>
+constexpr inline auto upper_bound<__nv_bfloat16>() -> __nv_bfloat16
+{
+  // Positive infinity in bfloat16 (sign=0, exp=all ones, mantissa=0)
+  return static_cast<__nv_bfloat16>(__bfloat16_constexpr{0x7f80u});
+}
+
 }  // namespace raft