According to this article in the Saigon Times, casinos in Macau remain the primary source of money laudnering for wealthy people from Mainland China. It refers to a report by China's national bank which estimates that in 2013, over $202 billion was illicitly removed from China and funelled to Macau through VIP gaming rooms. Most of that activity is under the control of junket operators who move funds from the Mainland, through Hong Kong financial institutions, to Macau. Funds are often then moved to what are called offshore financial centres (tax havens) under beneficial ownership structures to hide the names of the trustees, and are accessed for immigration purposes in places like Canada and the US.
As the Chinese government continues its crackdown on corruption in its so-called "tigers" and "flies" campaign, revenues in Macau have dropped, appearing to confirm the dependence of Macau casinos on junket VIP clients from China for movements of funds.