Viacom shareholders will receive 0.59625 CBS shares for each share they own. This will mean a slight premium to Viacom’s closing price on Monday.

Viacom’s market capitalization is currently $13.3 billion; CBS' is $18.5 billion.

Tuesday morning trading shows Viacom shares are up 1.5% to $33.05; CBS are 2.4% higher to $49.24.

Bob Bakish, president-CEO of Viacom, is expected to be named CEO of the new company. Joe Ianniello, president and acting CEO of CBS, is expected to be named chairman-CEO of CBS Networks. Ianniello's responsibilities will not include the Showtime cable network and book publisher Simon & Schuster.

The deal would be a long, hard win for Shari Redstone, president of National Amusements and vice-chair of CBS Corp. and Viacom, who has tried for the past several years to re-merge the companies. The two companies, controlled by National Amusements, had been one company from 1999 to 2006. 

The re-merger has been expected for some time, say analysts -- albeit a bit late -- especially considering other rising traditional media companies’ consolidations, as well as stronger digital media competition.