Nielsen Media Research (NMR) is an American firm that measures media audiences, including television, radio, theatre films (via the AMC Theatres MAP program) and newspapers. NMR, headquartered in New York City, is best known for the Nielsen ratings, an audience measurement system of television viewership that for years has been the deciding factor in canceling or renewing television shows by television networks. As of May 2012, it is part of Nielsen Holdings. Nielsen Media Research, once one of the largest media research companies in the world, began as a division of ACNielsen, a marketing research firm. In 1996, Nielsen Media Research was split off into an independent company and in 1999, was purchased by the Dutch conglomerate VNU. In 2001, VNU also purchased ACNielsen, thereby bringing both companies under the same corporate umbrella. VNU was reorganized and renamed the Nielsen Company in 2007.