Philip Morris drove the Dow Jones industrial average to its biggest gain in more than three weeks today as investors applauded the company's plan to acquire the snack food business Nabisco Holdings.

The deal, one of several mergers to which the market reacted today, boosted investors' enthusiasm and helped many take their focus off the Federal Reserve's meeting this week.

The Dow average rose 138.24 to close at 10,542.99, its largest point gain since June 2nd.

Broader stock indicators were also higher. The Standard and Poor's 500 index was up 13.83, at 1,455.31, and the Nasdaq composite index was up 66.78, at 3,912.12.