American sports bettors who patronize internationally licensed online gambling sites are facing new difficulties in funding their betting accounts.

Industry sources have informed CalvinAyre.com that a number of payment processors that do business with US-facing betting sites have recently received letters from credit card giant Visa expressing suspicions that these processors are handling illegal gambling transactions.

For US financial institutions, tracking the volume of fraudulent and/or miscoded transactions – aka transaction laundering – that flow through their systems is like finding needles in haystacks. But these institutions are now employing big data techniques, including intelligent risk models and machine learning algorithms to detect unauthorized transactions.

In the case of these gambling payment processors, algorithms have likely detected (among other things) rises in the number of customers who’ve begun spending significant amounts on new (for them) products or services, such as the infamous sporting goods and flower deliveries that led prosecutors to drop the legal hammer on online poker companies back in 2011.