diff --git a/NEWS b/NEWS
index 165496a50..de62d0613 100644
--- a/NEWS
+++ b/NEWS
@@ -2,6 +2,13 @@ This documents significant changes in the 1.0 branch of ksh 93u+m.
 For full details, see the git log at: https://github.com/ksh93/ksh/tree/1.0
 Uppercase BUG_* IDs are shell bug IDs as used by the Modernish shell library.
 
+2022-08-16:
+
+- Fixed an old bug in history expansion (set -H) where any use of the history
+  comment character caused processing to be aborted as if it were an invalid
+  history expansion. (On 2022-01-24 the history comment character was set to
+  '#' instead of being disabled by default, which exposed this bug.)
+
 2022-08-08:
 
 - Release 1.0.2.
diff --git a/src/cmd/ksh93/edit/hexpand.c b/src/cmd/ksh93/edit/hexpand.c
index 8c421cb36..df0add186 100644
--- a/src/cmd/ksh93/edit/hexpand.c
+++ b/src/cmd/ksh93/edit/hexpand.c
@@ -42,7 +42,8 @@ NoN(hexpand)
 static char *modifiers = "htrepqxs&";
 static int mod_flags[] = { 0, 0, 0, 0, HIST_PRINT, HIST_QUOTE, HIST_QUOTE|HIST_QUOTE_BR, 0, 0 };
 
-#define	DONE()	{flag |= HIST_ERROR; cp = 0; stakseek(0); goto done;}
+#define DONE		{ stakseek(0); goto done; }
+#define ERROROUT	{ flag |= HIST_ERROR; DONE; }
 
 struct subst
 {
@@ -127,6 +128,16 @@ static char *parse_subst(const char *s, struct subst *sb)
 	return cp;
 }
 
+/*
+ * return true if c is a word boundary character, i.e. the
+ * character following c is considered to start a new word
+ */
+
+static int is_wordboundary(char c)
+{
+	return isspace(c) || strchr("|&;()`<>",c);
+}
+
 /*
  * history expansion main routine
  */
@@ -200,11 +211,19 @@ int hist_expand(const char *ln, char **xp)
 			continue;
 		}
 
-		if(hc[2] && *cp == hc[2]) /* history comment designator, skip rest of line */
+		if(hc[2] && *cp == hc[2])
 		{
-			stakputc(*cp++);
-			stakputs(cp);
-			DONE();
+			if(cp == ln || is_wordboundary(cp[-1]))
+			{
+				/* word begins with history comment character; skip rest of line */
+				stakputs(cp);
+				DONE;
+			}
+			else
+			{
+				stakputc(*cp++);
+				continue;
+			}
 		}
 
 		n = -1;
@@ -322,7 +341,7 @@ getline:
 			*cp = '\0';
 			errormsg(SH_DICT, ERROR_ERROR, "%s: event not found", evp);
 			*cp = c;
-			DONE();
+			ERROROUT;
 		}
 
 		if(str) /* string search: restore orig. line */
@@ -427,7 +446,7 @@ getline:
 			*cp = '\0';
 			errormsg(SH_DICT, ERROR_ERROR, "%s: bad word specifier", evp);
 			*cp = c;
-			DONE();
+			ERROROUT;
 		}
 
 		/* no valid word designator after colon, rewind */
@@ -488,7 +507,7 @@ getsel:
 			*cp = '\0';
 			errormsg(SH_DICT, ERROR_ERROR, "%s: bad word specifier", evp);
 			*cp = c;
-			DONE();
+			ERROROUT;
 		}
 		else if(w[1] == -2)	/* skip last word */
 			sfseek(tmp, i, SEEK_SET);
@@ -548,7 +567,7 @@ getsel:
 			else
 			{
 				errormsg(SH_DICT, ERROR_ERROR, "%c: unrecognized history modifier", c);
-				DONE();
+				ERROROUT;
 			}
 
 			if(c == 'h' || c == 'r') /* head or base */
@@ -608,7 +627,7 @@ getsel:
 						(flag & HIST_QUICKSUBST) ? ":s" : "",
 						evp);
 					*cp = c;
-					DONE();
+					ERROROUT;
 				}
 
 				/* need pointer for strstr() */
@@ -636,7 +655,7 @@ getsel:
 							(flag & HIST_QUICKSUBST) ? ":s" : "",
 							evp);
 						*cp = c;
-						DONE();
+						ERROROUT;
 					}
 					/* loop if g modifier specified */
 					if(!tempcp || !(flag & HIST_GLOBALSUBST))
diff --git a/src/cmd/ksh93/include/version.h b/src/cmd/ksh93/include/version.h
index 7a0265db8..65fc12eea 100644
--- a/src/cmd/ksh93/include/version.h
+++ b/src/cmd/ksh93/include/version.h
@@ -17,8 +17,8 @@
 #include <releaseflags.h>
 
 #define SH_RELEASE_FORK	"93u+m"		/* only change if you develop a new ksh93 fork */
-#define SH_RELEASE_SVER	"1.0.2"		/* semantic version number: https://semver.org */
-#define SH_RELEASE_DATE	"2022-08-08"	/* must be in this format for $((.sh.version)) */
+#define SH_RELEASE_SVER	"1.0.3-alpha"	/* semantic version number: https://semver.org */
+#define SH_RELEASE_DATE	"2022-08-16"	/* must be in this format for $((.sh.version)) */
 #define SH_RELEASE_CPYR	"(c) 2020-2022 Contributors to ksh " SH_RELEASE_FORK
 
 /* Scripts sometimes field-split ${.sh.version}, so don't change amount of whitespace. */
diff --git a/src/cmd/ksh93/tests/pty.sh b/src/cmd/ksh93/tests/pty.sh
index ecdf949e6..7e00fc760 100755
--- a/src/cmd/ksh93/tests/pty.sh
+++ b/src/cmd/ksh93/tests/pty.sh
@@ -1021,5 +1021,30 @@ u Done
 u Done
 u Done
 !
+
+((SHOPT_HISTEXPAND)) && HISTFILE=$tmp/tmp_histfile tst $LINENO <<"!"
+L history expansion: history comment character stops line from being processed
+# https://github.com/ksh93/ksh/issues/513
+
+d 15
+p :test-1:
+w set -H
+p :test-2:
+w true ${#v} !non_existent
+r true \$\{#v} !non_existent\r\n$
+r : !non_existent: event not found
+w histchars='!^@'
+p :test-3:
+w true \\@ !non_existent
+r true \\@ !non_existent\r\n$
+r : !non_existent: event not found
+p :test-4:
+w true @ !non_existent
+r true @ !non_existent\r\n$
+p :test-5:
+w true OK
+r true OK\r\n$
+!
+
 # ======
 exit $((Errors<125?Errors:125))