diff --git a/git-am.sh b/git-am.sh
index 3af351ffaaf..3b770281232 100755
--- a/git-am.sh
+++ b/git-am.sh
@@ -300,6 +300,7 @@ split_patches () {
 		;;
 	stgit)
 		this=0
+		test 0 -eq "$#" && set -- -
 		for stgit in "$@"
 		do
 			this=$(expr "$this" + 1)
@@ -321,7 +322,7 @@ split_patches () {
 					print "Subject: ", $_ ;
 					$subject = 1;
 				}
-			' < "$stgit" > "$dotest/$msgnum" || clean_abort
+			' -- "$stgit" >"$dotest/$msgnum" || clean_abort
 		done
 		echo "$this" > "$dotest/last"
 		this=
@@ -329,6 +330,7 @@ split_patches () {
 		;;
 	hg)
 		this=0
+		test 0 -eq "$#" && set -- -
 		for hg in "$@"
 		do
 			this=$(( $this + 1 ))
@@ -345,17 +347,17 @@ split_patches () {
 				elsif (/^\# User /) { s/\# User/From:/ ; print ; }
 				elsif (/^\# Date /) {
 					my ($hashsign, $str, $time, $tz) = split ;
-					$tz = sprintf "%+05d", (0-$tz)/36;
+					$tz_str = sprintf "%+05d", (0-$tz)/36;
 					print "Date: " .
 					      strftime("%a, %d %b %Y %H:%M:%S ",
-						       localtime($time))
-					      . "$tz\n";
+						       gmtime($time-$tz))
+					      . "$tz_str\n";
 				} elsif (/^\# /) { next ; }
 				else {
 					print "\n", $_ ;
 					$subject = 1;
 				}
-			' <"$hg" >"$dotest/$msgnum" || clean_abort
+			' -- "$hg" >"$dotest/$msgnum" || clean_abort
 		done
 		echo "$this" >"$dotest/last"
 		this=
diff --git a/t/t4150-am.sh b/t/t4150-am.sh
index 6ced98cfb4a..3320fa6315e 100755
--- a/t/t4150-am.sh
+++ b/t/t4150-am.sh
@@ -104,6 +104,38 @@ test_expect_success setup '
 		echo "X-Fake-Field: Line Three" &&
 		git format-patch --stdout first | sed -e "1d"
 	} > patch1-ws.eml &&
+	{
+		sed -ne "1p" msg &&
+		echo &&
+		echo "From: $GIT_AUTHOR_NAME <$GIT_AUTHOR_EMAIL>" &&
+		echo "Date: $GIT_AUTHOR_DATE" &&
+		echo &&
+		sed -e "1,2d" msg &&
+		echo &&
+		echo "Signed-off-by: $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL>" &&
+		echo "---" &&
+		git diff-tree --no-commit-id --stat -p second
+	} >patch1-stgit.eml &&
+	mkdir stgit-series &&
+	cp patch1-stgit.eml stgit-series/patch &&
+	{
+		echo "# This series applies on GIT commit $(git rev-parse first)" &&
+		echo "patch"
+	} >stgit-series/series &&
+	{
+		echo "# HG changeset patch" &&
+		echo "# User $GIT_AUTHOR_NAME <$GIT_AUTHOR_EMAIL>" &&
+		echo "# Date $test_tick 25200" &&
+		echo "#      $(git show --pretty="%aD" -s second)" &&
+		echo "# Node ID $_z40" &&
+		echo "# Parent  $_z40" &&
+		cat msg &&
+		echo &&
+		echo "Signed-off-by: $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL>" &&
+		echo &&
+		git diff-tree --no-commit-id -p second
+	} >patch1-hg.eml &&
+
 
 	sed -n -e "3,\$p" msg >file &&
 	git add file &&
@@ -187,6 +219,56 @@ test_expect_success 'am applies patch e-mail with preceding whitespace' '
 	test "$(git rev-parse second^)" = "$(git rev-parse HEAD^)"
 '
 
+test_expect_success 'am applies stgit patch' '
+	rm -fr .git/rebase-apply &&
+	git checkout -f first &&
+	git am patch1-stgit.eml &&
+	test_path_is_missing .git/rebase-apply &&
+	git diff --exit-code second &&
+	test_cmp_rev second HEAD &&
+	test_cmp_rev second^ HEAD^
+'
+
+test_expect_success 'am --patch-format=stgit applies stgit patch' '
+	rm -fr .git/rebase-apply &&
+	git checkout -f first &&
+	git am --patch-format=stgit <patch1-stgit.eml &&
+	test_path_is_missing .git/rebase-apply &&
+	git diff --exit-code second &&
+	test_cmp_rev second HEAD &&
+	test_cmp_rev second^ HEAD^
+'
+
+test_expect_success 'am applies stgit series' '
+	rm -fr .git/rebase-apply &&
+	git checkout -f first &&
+	git am stgit-series/series &&
+	test_path_is_missing .git/rebase-apply &&
+	git diff --exit-code second &&
+	test_cmp_rev second HEAD &&
+	test_cmp_rev second^ HEAD^
+'
+
+test_expect_success 'am applies hg patch' '
+	rm -fr .git/rebase-apply &&
+	git checkout -f first &&
+	git am patch1-hg.eml &&
+	test_path_is_missing .git/rebase-apply &&
+	git diff --exit-code second &&
+	test_cmp_rev second HEAD &&
+	test_cmp_rev second^ HEAD^
+'
+
+test_expect_success 'am --patch-format=hg applies hg patch' '
+	rm -fr .git/rebase-apply &&
+	git checkout -f first &&
+	git am --patch-format=hg <patch1-hg.eml &&
+	test_path_is_missing .git/rebase-apply &&
+	git diff --exit-code second &&
+	test_cmp_rev second HEAD &&
+	test_cmp_rev second^ HEAD^
+'
+
 test_expect_success 'setup: new author and committer' '
 	GIT_AUTHOR_NAME="Another Thor" &&
 	GIT_AUTHOR_EMAIL="a.thor@example.com" &&