The Big Three credit rating agencies are S&P Global Ratings (S&P), Moody's, and Fitch Group. S&P and Moody's are based in the US, while Fitch is dual-headquartered in New York City and London, and is controlled by Hearst. As of 2013 they hold a collective global market share of "roughly 95 percent" with Moody's and Standard & Poor's having approximately 40% each, and Fitch around 15%.
According to an analysis by Deutsche Welle, "their special status has been cemented by law — at first only in the United States, but then in Europe as well." From the mid-1990s until early 2003, the Big Three were the only "Nationally Recognized Statistical Rating Organizations (NRSROs)" in the United States — a designation meaning they were used by the US government in several regulatory areas. (Four other NRSROs merged with Fitch in the 1990s.)
The Asian credit rating market is relatively diverse. Due to the regulation by the China central government, the Big 3 penetration into the domestic market especially in China is considered less competitive than the local well-recognized agencies, namely China Chengxin International (CCXI), China Lianhe Credit Rating (Lianhe Ratings), New Century Zixin Assessment Investment Service, Pengyuan Credit Rating etc.