Goldman revamps electronic stock trading to catch rival

Raj Mahajan achieved a rare when he rejoined Goldman Sachs Group Inc last year with the coveted title of partner, the Wall Street bank's highest rank. Goldman hired the tech-savvy Mahajan to revamp the business in March 2015. Since then, he has hired dozens of technologists and support staff to elevate Goldman's position in a fast-growing slice of the market and win back business from its chief competitor, Morgan Stanley .