A securities lawsuit could have big ramifications for cryptocurrency in the United States.

The case involves a man who allegedly worked at a crypto exchange and bought tokens based on his insider knowledge that they would be listed at the exchange and thus increase in value.

Although he faces criminal charges from the Department of Justice, Wired explains it’s a civil case from the Securities and Exchange Commission that could be more significant. That’s because they aren’t just accusing the man of insider trading but also securities fraud.

The key isn’t so much whether the man did what he’s accused of, but rather whether the court agrees with the SEC’s argument that the cryptocurrencies count as securities. That’s a longstanding question as the classification dates back to 1933 and was debatably vague even before technology evolved.

If cryptocurrencies are indeed securities (specifically “investment contracts”), then theoretically anyone issuing them would need to register with the SEC and follow its disclosure rules. Failing to do so could carry a prison sentence of up to five years.

The opposing argument is that cryptocurrencies are not securities because they don’t change in value based on any underlying factor such as a company’s profits. Instead, the limited supply means their value depends solely on demand and supply, making them commodities.

There’s also a school of thought that the SEC should regulate cryptocurrency issues, but impose looser regulations. While that’s even made it to proposed bills in Congress, there’s no clear sign they will succeed.