Before the bell: Futures lower after Microsoft's Yahoo deal fails

Warren Buffett's Berkshire Hathaway (NYSE: BRK.A) reported a 64% drop in quarterly profit late Friday. At the company's annual meeting this past weekend, the legendary investor said that while a Berkshire unit has bought portfolios of subprime mortgages (and has frozen resets that were due to send interest rates on those loans higher) he warned investors that housing-market weakness isn't over yet and predicted more losses for banks. At the same time, Buffett said Sunday he will consider investing in the insurance business of U.K. banking giant Royal Bank of Scotland (NYSE: RBS) and is close to buying a medium-sized company in the country.

Hovnanian Enterprises Inc. (NYSE: HOV) estimated on Monday it would take $225 million to $275 million of land-related charges for the that fiscal second-quarter and said that home deliveries dropped 21% to 2,494 homes in the period. The company also turned cash-flow positive faster than it expected and tripled its full-year estimate of cash flow.

After being rejected by Continental Airlines Inc. (NYSE: CAL) last month, United Airlines parent UAL Corp. (NYSE: UAUA) is intensifying merger talks with US Airways Group Inc. (NYSE: LCC), according to The Wall Street Journal. A deal is said could emerge in as soon as 10 days. In light of rising fuel costs, the more than $1.5 billion in potential cost savings and revenue enhancements the companies see from joining forces is no doubt appealing more and more.

Bristol-Myers Squibb (NYSE: BMY) will sell its ConvaTec wound therapy unit to Nordic Capital Fund VII and Avista Capital Partners for $4.1 billion.

Altria (NYSE: MO) shares are trading 1% higher in premarket trading. Bloomberg reports that the tobacco company said it will raise prices on its top-selling Marlboro and other cigarette brands as of May 5. The company will reduce discounts to distributors or increase list prices.

The Canadian Auto Workers, 9,000 of which work for Ford in Canada, voted to ratify a three-year contract with Ford Motor Co. (NYSE: F), an agreement the union expects Chrysler LLC and General Motors Corp. (NYSE: GM) to match. The deal keeps Ford's labor costs essentially the same as they are now, the union said.

Apple vs. Dell -- Fortune looks at the differences, starting at the top of course.