A gaming analyst in Macau told the South China Morning Post that an estimated $90 Billion in gaming revenue in Macau was unreported in 2013. Officially, the gaming industry and casinos in Macau reported $45 Billion in revenue in 2013.
One of the main methods of avoiding currency controls is through the use of payment cards issued by UnionPay. These mobile cards are registered as domestic transactions and thus are not limited to caps on how much a person can gamble in Macau. The gamblers who use these cards are able to either wash more money or use the casinos to avoid paying taxes in China.
Previously, when gamblers in Macau would run out of funds, they would visit pawn shops in order to sell items to cover their gambling debts. Due to the use of mobile payment cards, the Macau General Chamber of Pawnbrokers stated that business revenue is down 40 percent as less gamblers need to sell items.
Source: Toh Han Shih and Niall Fraser, “Mainland crackdown on illegal use of payment cards in Macau casinos,” South China Morning Post, May 8, 2014.