The Dow Jones industrial average rose 50.58 to 5,637.72. The well-known index of big American companies had skidded Friday as money managers locked in profits on the last day of a turbulent, but lucrative first quarter. On the first day of the new quarter, the institutional money began to flow back in, analysts said.

On the New York Stock Exchange, 1,461 issues rose, 929 fell and 722 were unchanged. Volume totaled 390.24 million shares vs. 413.04 million on Friday.

Broad-market indicators also were higher. The NYSE composite rose 4.02 to 350.94. The S&P 500 list rose 8.23 to 653.73, and the Nasdaq composite rose 4.29 to 1,105.69. The Amex market value index rose 1.06 to 572.44.

Two huge mergers dominated the news this morning. SBC Communications said it would acquire Pacific Telesis Group for about $16.7 billion. Also today, Aetna Life and Casualty said it will acquire U.S. Healthcare Inc. in an $8.9 billion deal.

"The new quarter has commenced with a spring surge. These big acquisitions and mergers have spurred the market," said Alan Ackerman, senior vice president at Fahnestock & Co. in New York.

Monday's economic news had little impact on markets, analysts said. Bonds were slightly higher after dipping on a morning report showing signs of a possible turnaround in the nation's slumping manufacturing sector.

Bonds and other fixed-income investments tend to increase in value when the economy is sluggish and the Federal Reserve is inclined to cut interest rates to spur business activity.