Wall St ends lower after shooting at Canadian parliament

NEW YORK: US stocks erased earlier gains to close lower on Wednesday as a shooting at the Canadian parliament unnerved investors, Boeing and Biogen sold off following results, and energy stocks fell along with oil prices.

Indexes had traded in positive territory for much of the session, putting the S&P 500 on track for a fifth straight day of gains. Earnings initially drove the move higher, with technology and material shares up on the back of strong results.