Traders on the floor of the New York Stock Exchange.

AutoNation –The auto retailer posted its best July sales numbers since 2006, selling 27,484 new vehicles during the month. That represented an eight percent increase over a year earlier.

Cardinal Health –The drug wholesaler and distributor scored a two cent beat with its latest quarterly earnings of 83 cents per share, excluding certain items. The company noted that those results came amid a year of significant transition for the industry overall.

Michael Kors –The luxury goods maker reported fiscal first quarter profit of 91 cents per share, beating estimates by 10 cents, and also saw revenue well above forecasts on the strength of a 24.2 percent increase in same-store sales.

Check out which companies are making headlines before the bell:

Berkshire Hathaway—Warren Buffett's company beat Street estimates on both the top and bottom lines. Profit jumped 41 percent from a year earlier, both from improved business results and healthy investment gains.

McDonald's–The restaurant chain will resume serving a full menu in Beijing and other Chinese cities this week, after a scandal at one of its suppliers forced it to cut back on some of its popular offerings.

Symantec–The company is among the companies excluded from China's list of approved anti-virus software providers, according to a Chinese media report. That report said the country is moving to limit use of foreign technology.

Goldman Sachs–Goldman is close to a deal to buy a stake in instant messaging service Perzo, according to Reuters.

General Motors–GM is looking for an alternative source of supplies in the China market after an explosion in Jiangsu ripped through a supplier factory and killed at least 69 people.

Amgen–Amgen reported positive results for a new cancer drug in a late-stage study, saying it improved the length of time patients survived without the disease worsening.

Microsoft–The software giant is suing Samsung, claiming that Samsung refused to make patent royalty payments after Microsoft announced it would be acquiring Nokia's handset business.

Evercore Partners–Evercore has struck a deal to buy research firm ISI Group, and will combine it with its Institutional Equities business.

—By CNBC's Peter Schacknow

Questions? Comments? Email us at marketinsider@cnbc.com