Name that company

I trace my roots back to 1927, when a talent agent created a radio broadcasting system for his clients to perform on. I soon merged with Columbia Phonograph and Records, and later entered television. (Westinghouse Electric bought me in 1995.) My current name reflects a big media merger that closed in December 2019, reuniting two businesses that used to be under one roof. I’m part of the National Amusements holding company. My portfolio boasts Showtime Networks, Paramount Pictures, Nickelodeon, MTV, Comedy Central, BET, Pluto TV and Simon & Schuster. I reach more than 4.3 billion subscribers globally. Who amI?

Last week’s answer: Stanley Black & Decker