A press release from the US Securities Exchange Commission has declared that it is indicting a now-defunct exchange on charges of fraud: BitFunder Charged With Fraud By US SEC
The New York Director said:

We allege that BitFunder operated unlawfully as an unregistered securities exchange. Platforms that engage in the activity of a national securities exchange, regardless of whether that activity involves digital assets, tokens, or coins, must register with the SEC or operate pursuant to an exemption.