US credit card market: Visa – 44%, MasterCard – 31%, AmEx – 20%, Discover – 5%

Visa had a 44% share of the US credit card market in 2006, compared to MasterCard’s 31%, AmEx’s 20% and Discover’s 5%. The same report said Visa had a 48% market share of the US debit card market, compared to 14% at MasterCard, Nilson Report says.