The Sensex at the Bombay Stock Exchange closed 128 points, or 0.7 percent higher, at 18,943, on Monday. Earlier during the session, the Sensex had crossed the key 19,000-point mark, but could not hold on to those gains. The Nifty at the National Stock Exchange rose 33 points, or 0.6 percent, to 5,687. The benchmark index has already rallied more than 975 points in the last four trading sessions.