diff --git a/json_tokener.c b/json_tokener.c
index 48d4109..94d43b4 100644
--- a/json_tokener.c
+++ b/json_tokener.c
@@ -762,7 +762,14 @@ struct fjson_object *fjson_tokener_parse_ex(struct fjson_tokener *tok, const cha
 					printbuf_memappend_fast(tok->pb, case_start, case_len);
 
 				// Check for -Infinity
-				if (tok->pb->buf[0] == '-' && case_len == 1 && (c == 'i' || c == 'I')) {
+				// Use bpos (the total number of bytes buffered so far)
+				// rather than case_len (only what this call appended), so
+				// that "-" and "Infinity" split across incremental calls
+				// are still recognized. Reset st_pos, which may carry a
+				// stale value from a previously parsed token.
+				if (tok->pb->bpos == 1 && tok->pb->buf[0] == '-' &&
+				    (c == 'i' || c == 'I')) {
+					tok->st_pos = 0;
 					state = fjson_tokener_state_inf;
 					goto redo_char;
 				}