Struggling oil dips below $30; Wall St. rally stalls

By Lewis Krauskopf NEW YORK (Reuters) - Oil prices tumbled again on Tuesday with U.S. crude diving briefly below $30 a barrel, taking down energy shares and undercutting a rally in stocks. Volatile Chinese markets and the deepening oil slide have shaken sentiment in equities to start 2016. "I do think oil is a major driver," said Brad McMillan, chief investment officer for Commonwealth Financial in Waltham, Massachusetts.