Indices closed well into red territory on Monday. Exxon Mobil led the Dow’s 4.6% downswing on a drop in oil prices. Oil slipped 1.9% to settle at $64.24 a barrel. Meanwhile, services industry activity increased in January. The ISM non-manufacturing index jumped to 59.9 from 56 in December. In earnings moves, Bristol-Myers Squibb reported fourth-quarter profit of 68 cents a share, which exceeded expectations by a penny. Revenue climbed to $5.45 billion from $5.24 billion. Analysts anticipated revenue of $5.35 billion.