Crypto entrepreneur Do Kwon’s lawyers say a US regulator’s lawsuit accusing him and Terraform Labs Pte of securities fraud is unfounded, in part, because the stablecoin at issue is a currency, not a security.

US law prohibits regulators “from using federal securities law to assert jurisdiction over the digital assets in this case,” Kwon’s lawyers said Friday in a request to a judge to dismiss the lawsuit.

The US Securities and Exchange Commission sued Kwon and the company he co-founded, Terraform Labs, in February, accusing them of fraud related to the collapse of the TerraUSD stablecoin.

Kwon’s lawyers say the lawsuit is an improper attempt by the SEC to regulate cryptocurrencies using antiquated laws, even though Congress, the executive branch and the agency itself can’t agree on what qualifies as a “security.”