Some key dates in NBC's history:
1926: National Broadcasting Co. formed by General Electric Co., Westinghouse Electric Co. and Radio Corporation of America after buying broadcast assets from AT&T. Launches first permanent radio network in United States.
1931: Experimental TV broadcasts begin from atop Empire State Building.
1932: RCA becomes sole owner of NBC.
1939: NBC begins regular television broadcasts in New York, with opening of World's Fair.
1941: NBC and CBS stations in New York get nation's first commercial television licenses.
1943: ABC gets its start after NBC sells one of its two radio networks under pressure from government.
1947: "Meet the Press" premieres.
1948: Comic Milton Berle becomes first television star on "Texaco Star Theater"
1948: Television ownership reaches 1 million.
1950: Trademark granted for three-note NBC chimes.
1952: Launch of "Today," first network early-morning news show.
1954: NBC makes first coast-to-coast color broadcast. "The Tonight Show" debuts with Steve Allen.
1962: Johnny Carson becomes "Tonight" host.
1964: NBC broadcasts its first Olympic Games.
1975: "Saturday Night Live" debuts.
1984: "The Cosby Show" debuts, becomes TV's biggest hit.
1986: GE restores its ties to NBC, becoming its owner after acquiring RCA.
1989: "Seinfeld" debuts.
1994: "ER" and "Friends" debut, making NBC's Thursday "must-see TV."
1995: Network launches NBC.com.
1996: NBC and Microsoft Corp. launch MSNBC on cable TV and Internet.
2002: NBC acquires Spanish-language broadcaster Telemundo and entertainment cable network Bravo.
2004: NBC Universal formed after merger with Vivendi Universal Entertainment.
2007: Jeff Zucker named president and chief executive.
2008: Launch of Hulu, online video joint venture with Fox network owner News Corp. ABC later joins.
2009: NBC, fourth in ratings with desires to pare down the costs of producing scripted shows, brings Jay Leno to prime time in bold move.
Sources: NBC, AP research