US stocks settled into the red Monday in a quiet market lacking significant economic news for direction.
The Dow Jones Industrial Average was down 36.66 points (0.28 percent) at 13,238.54 after an hour of trade (1430 GMT).
The S&P 500-stock index fell 4.96 (0.35 percent) to 1,413.20, while the tech-rich Nasdaq dropped 13.09 (0.43 percent) to 3,063.50.
"Market action is expected to be relatively quiet with no major economic data releases today," Wells Fargo Advisors analysts said.
Best Buy shares slid 7.3 percent to $18.80. Best Buy founder and largest shareholder Richard Schulze said Monday he was "shocked" that the board had rejected his bid to buy the struggling electronics retailer. The company announced a new chief executive specialized in turnarounds, Hubert Joly.
In merger and acquisition news, health insurance giant Aetna will buy Coventry Health Care, a large provider of government-financed health care such as Medicare and Medicaid, in a deal valued at $7.3 billion.
Aetna shares jumped 4.9 percent and Coventry soared 19.1 percent.
General Motors slipped 1.1 percent after the US government announced the automaker will recall more than 249,000 sport utility vehicles in the United States to fix a fire hazard.
The quiet action came after two straight days of gains had left the Dow on Friday at its highest level since the last days of 2007.
The Dow and the S&P each rose 0.2 percent and the Nasdaq added 0.5 percent.
US bond prices rose. The 10-year Treasury yield fell to 1.80 percent from 1.82 percent Friday, while the 30-year slipped to 2.92 percent from 2.93 percent. Bond yields move inversely to prices.