Money Laundering

 Financial regulation plays a big role in law enforcement, by helping investigators to follow the money, which is often easier than following the crimes that generate the money. So, for example, drug dealers and others have trouble turning their income (which is often in cash) into bank accounts that can be used to buy the things that legal money can buy.  Money laundering involves turning ill got gains into reportable income.  Gambling, it turns out, offers some possibilities: if I come into the casino with some cash, and come out with some cash, it's hard to prove that I'm paying tax on more than my winnings.

Here's a story that touches on that, from the WSJ:

Cantor Fitzgerald Gambling Affiliate to Pay $22.5 Million to Settle Probes. CG Technology is said to have admitted aiding and abetting illegal gambling and money laundering   By Kate O’Keeffe and Alexandra Berzon

"Cantor Fitzgerald LP’s sports-betting affiliate has agreed to pay $22.5 million in penalties and forfeiture to the U.S. government in conjunction with its involvement in illegal gambling and money laundering, according to people familiar with the matter.

...

"The agreement comes as the U.S. Treasury and Justice Departments have been increasingly focused in recent years on potential money-laundering violations at casinos. The probes generally center on how the gambling companies allegedly help to facilitate money laundering or fail to report suspicious activities.

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"Two people who were running their own illegal bookmaking operations elsewhere laundered money through Cantor as part of this system, the people said."