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.

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.

Acquiring CSX would be expensive for Berkshire, but it would still be accretive to its earnings, one analyst calculated.

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.

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,

VeriSign shares dropped after the company released the pricing of its previously announced underwritten secondary offering of its common stock by affiliates of Berkshire Hathaway. Shares were down 7% at $284.72 on Tuesday. The stock has been down 1.6% this month.

Its stock is still reasonably valued relative to its growth potential. Berkshire hasn't bought or sold any shares of American Express since 2012. Let's see why Buffett considered it to be such a reliable long-term investment -- and why it's a great place ...