The blockbuster deal raises the odds that Buffett’s Berkshire Hathaway, which owns the Burlington Northern Santa Fe railroad, will reach a deal with CSX to create a second transcontinental railroad. Union Pacific and BNSF compete in the western U.S., while CSX and Norfolk Southern are the two big Eastern railroads.

Here are some of the stories Wall Street is watching on Tuesday, July 29. Warren Buffett's Berkshire Hathaway (BRK-B, BRK-A) is trimming more of its stake in VeriSign (VRSN). Shares of Novo Nordisk (NVO) are being pummeled after warning of a slowdown in sales of its weight-loss drug in the US.

Kraft Heinz (NASDAQ:KHC) is considering undertaking a landmark separation of its business by spinning off a substantial part of its grocery division into a new, independently traded entity. The food giant's move follows years of lackluster growth,

The merger would create the United States’ first coast-to-coast rail network, spanning 50,000 miles and 43 states.

BERKSHIRE Hathaway sold about one-third of its stake in VeriSign, an internet infrastructure and domain name registry company that Warren Buffett’s conglomerate has invested in since 2012, VeriSign said on Monday.

The Sage of Omaha's company will make over $1.2 billion from the sale, according to an announcement on Monday.

There are a few key numbers investors will be watching when Berkshire reports its second-quarter results, expected on Saturday, Aug. 2. Berkshire's operating earnings from its businesses is the most obvious example. There's also the company's cash stockpile, which reached an all-time high of $347.7 billion at the end of the first quarter.

Berkshire Hathaway is a resilient investment with strong cash reserves, defensive value, and growth potential. Click here to read an analysis of BRK.A stock now.