Indices ended Wednesday’s session in green territory. Hewlett-Packard, Caterpillar, and Bank of America led the Dow’s upswing. Stocks gained on the first trading day of the year, after the House of Representatives managed to pass the Senate’s 11th-hour agreement aimed at averting the “fiscal cliff.” Meanwhile, manufacturing activity increased in December. The Institute for Supply Management’s index climbed to 50.7 from 49.5 in November. Economists had anticipated a lesser increase to 50.3 in December. On another note, crude oil tacked on $1.30 to settle at $93.12 a barrel. In merger moves, Avis announced plans to acquire Zipcar for about $500 million.