Stocks Open Week With Rally

Updated from 2:36 p.m. EDT

Stocks in the U.S. rose Monday as traders welcomed a downturn in oil prices and a potentially giant deal in the technology sector involving Hewlett-Packard (HPQ Quote).

The Dow Jones Industrial Average advanced 133 points, or 1%, to 12,880, and the S&P 500 swelled by 15 points, or 1.1%, at 1404. The Nasdaq Composite was the best-performing index, spiking 43 points, or 1.8%, to 2488.

Equity measures were strong for most of the day as last week's oil rally cooled off a bit, but picked up even more steam after The Wall Street Journal said H-P is in advanced talks to buy Electronic Data Systems (EDS Quote) for $12 billion to $13 billion, according to people familiar with the matter. ...