There were $3 trillion worth of corporate mergers in 2014. Comcast's proposed acquisition of fellow cable company Time Warner was the largest at $45 billion. Gene J. Puskar/AP hide caption

itoggle caption Gene J. Puskar/AP

Tobacco giant Reynolds American is buying Lorillard and acquiring Newport, a popular menthol cigarette. In a shrinking market, Newport is one of the few U.S. brands gaining market share. It is particularly popular among African-American smokers. Justin Sullivan/Getty Images hide caption

itoggle caption Justin Sullivan/Getty Images