Banks looking to expand into the wild world of crypto are getting a pointed reminder from regulators of the risks involved.

The Basel Committee on Banking Supervision said June 10 that they're planning to assign bitcoin, among other crypto products, the toughest capital requirements for any bank that wants to hold it. The standard setters said that the risks to financial stability would be significant if banks expanded their offerings in the volatile market.

On Monday, bitcoin declined about 10 percent, to a two-week low, after China announced that it summoned officials from its biggest banks to reiterate a ban on providing cryptocurrency services. It's the latest sign that China plans to do whatever it takes to close any loopholes left in crypto trading.