diff --git a/builtin/interpret-trailers.c b/builtin/interpret-trailers.c
index 033bd1556c..11f4ce9e4a 100644
--- a/builtin/interpret-trailers.c
+++ b/builtin/interpret-trailers.c
@@ -9,6 +9,7 @@
 #include "gettext.h"
 #include "parse-options.h"
 #include "string-list.h"
+#include "tempfile.h"
 #include "trailer.h"
 #include "config.h"
 
@@ -91,6 +92,102 @@ static int parse_opt_parse(const struct option *opt, const char *arg,
 	return 0;
 }
 
+static struct tempfile *trailers_tempfile;
+
+static FILE *create_in_place_tempfile(const char *file)
+{
+	struct stat st;
+	struct strbuf filename_template = STRBUF_INIT;
+	const char *tail;
+	FILE *outfile;
+
+	if (stat(file, &st))
+		die_errno(_("could not stat %s"), file);
+	if (!S_ISREG(st.st_mode))
+		die(_("file %s is not a regular file"), file);
+	if (!(st.st_mode & S_IWUSR))
+		die(_("file %s is not writable by user"), file);
+
+	/* Create temporary file in the same directory as the original */
+	tail = strrchr(file, '/');
+	if (tail)
+		strbuf_add(&filename_template, file, tail - file + 1);
+	strbuf_addstr(&filename_template, "git-interpret-trailers-XXXXXX");
+
+	trailers_tempfile = xmks_tempfile_m(filename_template.buf, st.st_mode);
+	strbuf_release(&filename_template);
+	outfile = fdopen_tempfile(trailers_tempfile, "w");
+	if (!outfile)
+		die_errno(_("could not open temporary file"));
+
+	return outfile;
+}
+
+static void read_input_file(struct strbuf *sb, const char *file)
+{
+	if (file) {
+		if (strbuf_read_file(sb, file, 0) < 0)
+			die_errno(_("could not read input file '%s'"), file);
+	} else {
+		if (strbuf_read(sb, fileno(stdin), 0) < 0)
+			die_errno(_("could not read from stdin"));
+	}
+}
+
+static void interpret_trailers(const struct process_trailer_options *opts,
+			       struct list_head *new_trailer_head,
+			       const char *file)
+{
+	LIST_HEAD(head);
+	struct strbuf sb = STRBUF_INIT;
+	struct strbuf trailer_block = STRBUF_INIT;
+	struct trailer_info info;
+	FILE *outfile = stdout;
+
+	trailer_config_init();
+
+	read_input_file(&sb, file);
+
+	if (opts->in_place)
+		outfile = create_in_place_tempfile(file);
+
+	parse_trailers(opts, &info, sb.buf, &head);
+
+	/* Print the lines before the trailers */
+	if (!opts->only_trailers)
+		fwrite(sb.buf, 1, info.trailer_block_start, outfile);
+
+	if (!opts->only_trailers && !info.blank_line_before_trailer)
+		fprintf(outfile, "\n");
+
+
+	if (!opts->only_input) {
+		LIST_HEAD(config_head);
+		LIST_HEAD(arg_head);
+		parse_trailers_from_config(&config_head);
+		parse_trailers_from_command_line_args(&arg_head, new_trailer_head);
+		list_splice(&config_head, &arg_head);
+		process_trailers_lists(&head, &arg_head);
+	}
+
+	/* Print trailer block. */
+	format_trailers(opts, &head, &trailer_block);
+	free_trailers(&head);
+	fwrite(trailer_block.buf, 1, trailer_block.len, outfile);
+	strbuf_release(&trailer_block);
+
+	/* Print the lines after the trailers as is */
+	if (!opts->only_trailers)
+		fwrite(sb.buf + info.trailer_block_end, 1, sb.len - info.trailer_block_end, outfile);
+	trailer_info_release(&info);
+
+	if (opts->in_place)
+		if (rename_tempfile(&trailers_tempfile, file))
+			die_errno(_("could not rename temporary file to %s"), file);
+
+	strbuf_release(&sb);
+}
+
 int cmd_interpret_trailers(int argc, const char **argv, const char *prefix)
 {
 	struct process_trailer_options opts = PROCESS_TRAILER_OPTIONS_INIT;
@@ -132,11 +229,11 @@ int cmd_interpret_trailers(int argc, const char **argv, const char *prefix)
 	if (argc) {
 		int i;
 		for (i = 0; i < argc; i++)
-			process_trailers(argv[i], &opts, &trailers);
+			interpret_trailers(&opts, &trailers, argv[i]);
 	} else {
 		if (opts.in_place)
 			die(_("no input file given for in-place editing"));
-		process_trailers(NULL, &opts, &trailers);
+		interpret_trailers(&opts, &trailers, NULL);
 	}
 
 	new_trailers_clear(&trailers);
diff --git a/pretty.c b/pretty.c
index cf964b060c..bdbed4295a 100644
--- a/pretty.c
+++ b/pretty.c
@@ -1759,7 +1759,7 @@ static size_t format_commit_one(struct strbuf *sb, /* in UTF-8 */
 				goto trailer_out;
 		}
 		if (*arg == ')') {
-			format_trailers_from_commit(sb, msg + c->subject_off, &opts);
+			format_trailers_from_commit(&opts, msg + c->subject_off, sb);
 			ret = arg - placeholder + 1;
 		}
 	trailer_out:
diff --git a/ref-filter.c b/ref-filter.c
index 0ec29f7385..03542d0236 100644
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -1991,7 +1991,7 @@ static void grab_sub_body_contents(struct atom_value *val, int deref, struct exp
 			struct strbuf s = STRBUF_INIT;
 
 			/* Format the trailer info according to the trailer_opts given */
-			format_trailers_from_commit(&s, subpos, &atom->u.contents.trailer_opts);
+			format_trailers_from_commit(&atom->u.contents.trailer_opts, subpos, &s);
 
 			v->s = strbuf_detach(&s, NULL);
 		} else if (atom->u.contents.option == C_BARE)
diff --git a/sequencer.c b/sequencer.c
index 5c6f541126..ea1441e617 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -332,7 +332,7 @@ static int has_conforming_footer(struct strbuf *sb, struct strbuf *sob,
 		sb->buf[sb->len - ignore_footer] = '\0';
 	}
 
-	trailer_info_get(&info, sb->buf, &opts);
+	trailer_info_get(&opts, sb->buf, &info);
 
 	if (ignore_footer)
 		sb->buf[sb->len - ignore_footer] = saved_char;
diff --git a/t/t4201-shortlog.sh b/t/t4201-shortlog.sh
index d7382709fc..f698d0c9ad 100755
--- a/t/t4201-shortlog.sh
+++ b/t/t4201-shortlog.sh
@@ -312,6 +312,38 @@ test_expect_success 'shortlog de-duplicates trailers in a single commit' '
 	test_cmp expect actual
 '
 
+# Trailers that have unfolded (single line) and folded (multiline) values which
+# are otherwise identical are treated as the same trailer for de-duplication.
+test_expect_success 'shortlog de-duplicates trailers in a single commit (folded/unfolded values)' '
+	git commit --allow-empty -F - <<-\EOF &&
+	subject one
+
+	this message has two distinct values, plus a repeat (folded)
+
+	Repeated-trailer: Foo foo foo
+	Repeated-trailer: Bar
+	Repeated-trailer: Foo
+	  foo foo
+	EOF
+
+	git commit --allow-empty -F - <<-\EOF &&
+	subject two
+
+	similar to the previous, but without the second distinct value
+
+	Repeated-trailer: Foo foo foo
+	Repeated-trailer: Foo
+	  foo foo
+	EOF
+
+	cat >expect <<-\EOF &&
+	     2	Foo foo foo
+	     1	Bar
+	EOF
+	git shortlog -ns --group=trailer:repeated-trailer -2 HEAD >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'shortlog can match multiple groups' '
 	git commit --allow-empty -F - <<-\EOF &&
 	subject one
diff --git a/trailer.c b/trailer.c
index ef9df4af55..57b4aa7d5a 100644
--- a/trailer.c
+++ b/trailer.c
@@ -5,7 +5,6 @@
 #include "string-list.h"
 #include "run-command.h"
 #include "commit.h"
-#include "tempfile.h"
 #include "trailer.h"
 #include "list.h"
 /*
@@ -145,12 +144,12 @@ static char last_non_space_char(const char *s)
 	return '\0';
 }
 
-static void print_tok_val(FILE *outfile, const char *tok, const char *val)
+static void print_tok_val(struct strbuf *out, const char *tok, const char *val)
 {
 	char c;
 
 	if (!tok) {
-		fprintf(outfile, "%s\n", val);
+		strbuf_addf(out, "%s\n", val);
 		return;
 	}
 
@@ -158,21 +157,22 @@ static void print_tok_val(FILE *outfile, const char *tok, const char *val)
 	if (!c)
 		return;
 	if (strchr(separators, c))
-		fprintf(outfile, "%s%s\n", tok, val);
+		strbuf_addf(out, "%s%s\n", tok, val);
 	else
-		fprintf(outfile, "%s%c %s\n", tok, separators[0], val);
+		strbuf_addf(out, "%s%c %s\n", tok, separators[0], val);
 }
 
-static void print_all(FILE *outfile, struct list_head *head,
-		      const struct process_trailer_options *opts)
+void format_trailers(const struct process_trailer_options *opts,
+		     struct list_head *trailers,
+		     struct strbuf *out)
 {
 	struct list_head *pos;
 	struct trailer_item *item;
-	list_for_each(pos, head) {
+	list_for_each(pos, trailers) {
 		item = list_entry(pos, struct trailer_item, list);
 		if ((!opts->trim_empty || strlen(item->value) > 0) &&
 		    (!opts->only_trailers || item->token))
-			print_tok_val(outfile, item->token, item->value);
+			print_tok_val(out, item->token, item->value);
 	}
 }
 
@@ -366,8 +366,8 @@ static int find_same_and_apply_arg(struct list_head *head,
 	return 0;
 }
 
-static void process_trailers_lists(struct list_head *head,
-				   struct list_head *arg_head)
+void process_trailers_lists(struct list_head *head,
+			    struct list_head *arg_head)
 {
 	struct list_head *pos, *p;
 	struct arg_item *arg_tok;
@@ -589,7 +589,7 @@ static int git_trailer_config(const char *conf_key, const char *value,
 	return 0;
 }
 
-static void ensure_configured(void)
+void trailer_config_init(void)
 {
 	if (configured)
 		return;
@@ -719,7 +719,7 @@ static void add_arg_item(struct list_head *arg_head, char *tok, char *val,
 	list_add_tail(&new_item->list, arg_head);
 }
 
-static void parse_trailers_from_config(struct list_head *config_head)
+void parse_trailers_from_config(struct list_head *config_head)
 {
 	struct arg_item *item;
 	struct list_head *pos;
@@ -735,8 +735,8 @@ static void parse_trailers_from_config(struct list_head *config_head)
 	}
 }
 
-static void parse_trailers_from_command_line_args(struct list_head *arg_head,
-						  struct list_head *new_trailer_head)
+void parse_trailers_from_command_line_args(struct list_head *arg_head,
+					   struct list_head *new_trailer_head)
 {
 	struct strbuf tok = STRBUF_INIT;
 	struct strbuf val = STRBUF_INIT;
@@ -775,17 +775,6 @@ static void parse_trailers_from_command_line_args(struct list_head *arg_head,
 	free(cl_separators);
 }
 
-static void read_input_file(struct strbuf *sb, const char *file)
-{
-	if (file) {
-		if (strbuf_read_file(sb, file, 0) < 0)
-			die_errno(_("could not read input file '%s'"), file);
-	} else {
-		if (strbuf_read(sb, fileno(stdin), 0) < 0)
-			die_errno(_("could not read from stdin"));
-	}
-}
-
 static const char *next_line(const char *str)
 {
 	const char *nl = strchrnul(str, '\n');
@@ -999,16 +988,16 @@ static void unfold_value(struct strbuf *val)
  * Parse trailers in "str", populating the trailer info and "head"
  * linked list structure.
  */
-static void parse_trailers(struct trailer_info *info,
-			     const char *str,
-			     struct list_head *head,
-			     const struct process_trailer_options *opts)
+void parse_trailers(const struct process_trailer_options *opts,
+		    struct trailer_info *info,
+		    const char *str,
+		    struct list_head *head)
 {
 	struct strbuf tok = STRBUF_INIT;
 	struct strbuf val = STRBUF_INIT;
 	size_t i;
 
-	trailer_info_get(info, str, opts);
+	trailer_info_get(opts, str, info);
 
 	for (i = 0; i < info->trailer_nr; i++) {
 		int separator_pos;
@@ -1034,99 +1023,18 @@ static void parse_trailers(struct trailer_info *info,
 	}
 }
 
-static void free_all(struct list_head *head)
+void free_trailers(struct list_head *trailers)
 {
 	struct list_head *pos, *p;
-	list_for_each_safe(pos, p, head) {
+	list_for_each_safe(pos, p, trailers) {
 		list_del(pos);
 		free_trailer_item(list_entry(pos, struct trailer_item, list));
 	}
 }
 
-static struct tempfile *trailers_tempfile;
-
-static FILE *create_in_place_tempfile(const char *file)
-{
-	struct stat st;
-	struct strbuf filename_template = STRBUF_INIT;
-	const char *tail;
-	FILE *outfile;
-
-	if (stat(file, &st))
-		die_errno(_("could not stat %s"), file);
-	if (!S_ISREG(st.st_mode))
-		die(_("file %s is not a regular file"), file);
-	if (!(st.st_mode & S_IWUSR))
-		die(_("file %s is not writable by user"), file);
-
-	/* Create temporary file in the same directory as the original */
-	tail = strrchr(file, '/');
-	if (tail)
-		strbuf_add(&filename_template, file, tail - file + 1);
-	strbuf_addstr(&filename_template, "git-interpret-trailers-XXXXXX");
-
-	trailers_tempfile = xmks_tempfile_m(filename_template.buf, st.st_mode);
-	strbuf_release(&filename_template);
-	outfile = fdopen_tempfile(trailers_tempfile, "w");
-	if (!outfile)
-		die_errno(_("could not open temporary file"));
-
-	return outfile;
-}
-
-void process_trailers(const char *file,
-		      const struct process_trailer_options *opts,
-		      struct list_head *new_trailer_head)
-{
-	LIST_HEAD(head);
-	struct strbuf sb = STRBUF_INIT;
-	struct trailer_info info;
-	FILE *outfile = stdout;
-
-	ensure_configured();
-
-	read_input_file(&sb, file);
-
-	if (opts->in_place)
-		outfile = create_in_place_tempfile(file);
-
-	parse_trailers(&info, sb.buf, &head, opts);
-
-	/* Print the lines before the trailers */
-	if (!opts->only_trailers)
-		fwrite(sb.buf, 1, info.trailer_block_start, outfile);
-
-	if (!opts->only_trailers && !info.blank_line_before_trailer)
-		fprintf(outfile, "\n");
-
-
-	if (!opts->only_input) {
-		LIST_HEAD(config_head);
-		LIST_HEAD(arg_head);
-		parse_trailers_from_config(&config_head);
-		parse_trailers_from_command_line_args(&arg_head, new_trailer_head);
-		list_splice(&config_head, &arg_head);
-		process_trailers_lists(&head, &arg_head);
-	}
-
-	print_all(outfile, &head, opts);
-
-	free_all(&head);
-	trailer_info_release(&info);
-
-	/* Print the lines after the trailers as is */
-	if (!opts->only_trailers)
-		fwrite(sb.buf + info.trailer_block_end, 1, sb.len - info.trailer_block_end, outfile);
-
-	if (opts->in_place)
-		if (rename_tempfile(&trailers_tempfile, file))
-			die_errno(_("could not rename temporary file to %s"), file);
-
-	strbuf_release(&sb);
-}
-
-void trailer_info_get(struct trailer_info *info, const char *str,
-		      const struct process_trailer_options *opts)
+void trailer_info_get(const struct process_trailer_options *opts,
+		      const char *str,
+		      struct trailer_info *info)
 {
 	size_t end_of_log_message = 0, trailer_block_start = 0;
 	struct strbuf **trailer_lines, **ptr;
@@ -1134,7 +1042,7 @@ void trailer_info_get(struct trailer_info *info, const char *str,
 	size_t nr = 0, alloc = 0;
 	char **last = NULL;
 
-	ensure_configured();
+	trailer_config_init();
 
 	end_of_log_message = find_end_of_log_message(str, opts->no_divider);
 	trailer_block_start = find_trailer_block_start(str, end_of_log_message);
@@ -1176,23 +1084,13 @@ void trailer_info_release(struct trailer_info *info)
 	free(info->trailers);
 }
 
-static void format_trailer_info(struct strbuf *out,
+static void format_trailer_info(const struct process_trailer_options *opts,
 				const struct trailer_info *info,
-				const char *msg,
-				const struct process_trailer_options *opts)
+				struct strbuf *out)
 {
 	size_t origlen = out->len;
 	size_t i;
 
-	/* If we want the whole block untouched, we can take the fast path. */
-	if (!opts->only_trailers && !opts->unfold && !opts->filter &&
-	    !opts->separator && !opts->key_only && !opts->value_only &&
-	    !opts->key_value_separator) {
-		strbuf_add(out, msg + info->trailer_block_start,
-			   info->trailer_block_end - info->trailer_block_start);
-		return;
-	}
-
 	for (i = 0; i < info->trailer_nr; i++) {
 		char *trailer = info->trailers[i];
 		ssize_t separator_pos = find_separator(trailer, separators);
@@ -1237,13 +1135,25 @@ static void format_trailer_info(struct strbuf *out,
 
 }
 
-void format_trailers_from_commit(struct strbuf *out, const char *msg,
-				 const struct process_trailer_options *opts)
+void format_trailers_from_commit(const struct process_trailer_options *opts,
+				 const char *msg,
+				 struct strbuf *out)
 {
+	LIST_HEAD(trailer_objects);
 	struct trailer_info info;
 
-	trailer_info_get(&info, msg, opts);
-	format_trailer_info(out, &info, msg, opts);
+	parse_trailers(opts, &info, msg, &trailer_objects);
+
+	/* If we want the whole block untouched, we can take the fast path. */
+	if (!opts->only_trailers && !opts->unfold && !opts->filter &&
+	    !opts->separator && !opts->key_only && !opts->value_only &&
+	    !opts->key_value_separator) {
+		strbuf_add(out, msg + info.trailer_block_start,
+			   info.trailer_block_end - info.trailer_block_start);
+	} else
+		format_trailer_info(opts, &info, out);
+
+	free_trailers(&trailer_objects);
 	trailer_info_release(&info);
 }
 
@@ -1253,7 +1163,7 @@ void trailer_iterator_init(struct trailer_iterator *iter, const char *msg)
 	strbuf_init(&iter->key, 0);
 	strbuf_init(&iter->val, 0);
 	opts.no_divider = 1;
-	trailer_info_get(&iter->internal.info, msg, &opts);
+	trailer_info_get(&opts, msg, &iter->internal.info);
 	iter->internal.cur = 0;
 }
 
@@ -1270,6 +1180,7 @@ int trailer_iterator_advance(struct trailer_iterator *iter)
 		strbuf_reset(&iter->val);
 		parse_trailer(&iter->key, &iter->val, NULL,
 			      trailer, separator_pos);
+		/* Always unfold values during iteration. */
 		unfold_value(&iter->val);
 		return 1;
 	}
diff --git a/trailer.h b/trailer.h
index 1644cd05f6..1d106b6dd4 100644
--- a/trailer.h
+++ b/trailer.h
@@ -81,15 +81,31 @@ struct process_trailer_options {
 
 #define PROCESS_TRAILER_OPTIONS_INIT {0}
 
-void process_trailers(const char *file,
-		      const struct process_trailer_options *opts,
-		      struct list_head *new_trailer_head);
+void parse_trailers_from_config(struct list_head *config_head);
 
-void trailer_info_get(struct trailer_info *info, const char *str,
-		      const struct process_trailer_options *opts);
+void parse_trailers_from_command_line_args(struct list_head *arg_head,
+					   struct list_head *new_trailer_head);
+
+void process_trailers_lists(struct list_head *head,
+			    struct list_head *arg_head);
+
+void parse_trailers(const struct process_trailer_options *,
+		    struct trailer_info *,
+		    const char *str,
+		    struct list_head *head);
+
+void trailer_info_get(const struct process_trailer_options *,
+		      const char *str,
+		      struct trailer_info *);
 
 void trailer_info_release(struct trailer_info *info);
 
+void trailer_config_init(void);
+void format_trailers(const struct process_trailer_options *,
+		     struct list_head *trailers,
+		     struct strbuf *out);
+void free_trailers(struct list_head *);
+
 /*
  * Format the trailers from the commit msg "msg" into the strbuf "out".
  * Note two caveats about "opts":
@@ -101,8 +117,9 @@ void trailer_info_release(struct trailer_info *info);
  *     only the trailer block itself, even if the "only_trailers" option is not
  *     set.
  */
-void format_trailers_from_commit(struct strbuf *out, const char *msg,
-				 const struct process_trailer_options *opts);
+void format_trailers_from_commit(const struct process_trailer_options *opts,
+				 const char *msg,
+				 struct strbuf *out);
 
 /*
  * An interface for iterating over the trailers found in a particular commit