diff --git a/semver/__init__.py b/semver/__init__.py
index b715a9c..37d34ab 100644
--- a/semver/__init__.py
+++ b/semver/__init__.py
@@ -67,7 +67,7 @@ class SemVer(object):
         merged_prefix = None
         matches = re.findall("[\/][^\/]+[\/]", self.merged_branch)
         if len(matches) > 1:
-            merged_prefix = matches[1][1:-1]
+            merged_prefix = matches[0][1:-1]
 
         if merged_prefix:
             for prefix in self.major_branches: