On the corporate front, shares of Lowe's ( LOW) closed down 5.8% after the home-improvement retailer posted second-quarter earnings of 64 cents a share on revenue of $14.25 billion, missing Wall Street's consensus on both the top and bottom lines. Best Buy ( BBY) was also in focus after the Minneapolis-based consumer electronics retailer named named Hubert Joly as its chief executive officer following a busy weekend of jousting with founder Richard Schulze regarding his efforts to take the company private. Joly previously served as CEO of hospitality and restaurant giant Carlson, whose businesses include the restaurant chain TGI Friday's. The stock lost 10.4%. Monday's big deal was in the insurance space as Aetna ( AET) agreed to purchase Coventry Health Care ( CVH ) in a transaction valued at $7.3 billion, including the assumption of debt. The deal valued Coventry shares at $42.08 in cash and Aetna stock as of Friday's close, a 20% premium. Aetna shares finished up 5.6%, while Coventry's stock jumped 20.3%. October crude oil futures fell 6 cents to settle at $96.26 a barrel, while December gold futures rose $3.60 to settle at $1622.60 an ounce. The benchmark 10-year Treasury was rising 2/32, diluting the yield to 1.814%. The greenback was off 0.12%, according to the dollar index.