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"[1] with Moody's and Standard & Poor's having approximately 40% each, and Fitch around 15%.[2]

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."[1][3] 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.)[4]

The European Union has considered setting up a state-supported EU-based agency.[5]

A common criticism of the Big Three, and one that was highly linked to bank failure in the 2008 recession, is the dominance the agencies had on the market. As the three agencies held 95% of the market share, there was very little room for competition. Many feel this was a crucial contributor to the toxic debt-instrument environment that led to the financial downturn. In a preliminary exchange of views in the European Parliament Committee on Economic and Monetary Affairs, held in late 2011, it was advocated that more competition should exist amongst rating agencies. The belief was that this would diminish conflicts of interest and create more transparent criteria for rating sovereign debt.

There are over one hundred national and regional rating agencies which could issue ratings if they can build up their credibility by meeting the conditions for being registered by European Securities and Markets Authority (ESMA). They could also use data from the European Securities and Markets Authority (ESMA). They could also use data from the European Central Bank and the International Monetary Fund to help with their analyses. Reliance on the "big three" could also be reduced by big companies assessing themselves, MEPs added.[10]

In November 2013, credit ratings organizations from five countries (CPR of Portugal, CARE Rating of India, GCR of South Africa, MARC of Malaysia, and SR Rating of Brazil) joint ventured to launch ARC Ratings, a new global agency touted as an alternative to the "Big Three".[11]