diff --git a/src/semiwrap/name_transform.py b/src/semiwrap/name_transform.py
index 7f34920..70dcc56 100644
--- a/src/semiwrap/name_transform.py
+++ b/src/semiwrap/name_transform.py
@@ -57,6 +57,7 @@ class NameTransforms:
 
 
 _WORD_RE = re.compile(r"[A-Z]+(?=[A-Z][a-z]|[0-9]|_|$)|[A-Z]?[a-z]+|[0-9]+|[A-Z]+")
+_CAPS_CASE_PART_RE = re.compile(r"[A-Z0-9]+")
 
 
 def _split_underscore_affixes(name: str) -> typing.Tuple[str, str, str]:
@@ -89,10 +90,12 @@ def _normalize_known_words(
 
 
 def _split_words_no_known_words(name: str) -> typing.List[str]:
+    parts = [part for part in name.replace("-", "_").split("_") if part]
+    if parts and all(_CAPS_CASE_PART_RE.fullmatch(part) for part in parts):
+        return parts
+
     words: typing.List[str] = []
-    for part in name.replace("-", "_").split("_"):
-        if not part:
-            continue
+    for part in parts:
         words.extend(m.group(0) for m in _WORD_RE.finditer(part))
     return words or [name]
 
diff --git a/tests/test_name_transform.py b/tests/test_name_transform.py
index b08bc05..725a067 100644
--- a/tests/test_name_transform.py
+++ b/tests/test_name_transform.py
@@ -20,6 +20,8 @@
         ("http_server", "http_server"),
         ("getFOO", "get_foo"),
         ("PascalCase_LikeThis", "pascal_case_like_this"),
+        ("CAN_S0", "can_s0"),
+        ("WPI_TIMESRC_V4L_EOF", "wpi_timesrc_v4l_eof"),
     ],
 )
 def test_snake_case_transform(source, expected):
@@ -115,6 +117,8 @@ def test_builtin_transforms_do_not_strip_non_k_camel_case_prefix():
         ("http_server", "HTTP_SERVER"),
         ("getFOO", "GET_FOO"),
         ("PascalCase_LikeThis", "PASCAL_CASE_LIKE_THIS"),
+        ("CAN_S0", "CAN_S0"),
+        ("WPI_TIMESRC_V4L_EOF", "WPI_TIMESRC_V4L_EOF"),
     ],
 )
 def test_caps_case_transform(source, expected):