The top U.S. futures regulator has denied a Freedom of Information Act (FOIA) request for subpoenas reportedly issued to crypto exchange Bitfinex and the closely-linked ‘stablecoin’ operator Tether, according to records obtained by CoinDesk.

The FOIA request, filed by an individual who requested anonymity when speaking to CoinDesk, sought “subpoenas issued to iFinex inc. also known as Bitfinex and it’s subsidiary companies, as well as subpoenas issued Tether Limited and its subsidiary companies” and was initially submitted in February.

The filing came weeks after reports first indicated that Bitfinex and Tether had been subpoenaed by the Commodity Futures Trading Commission (CFTC), though it’s not clear what, exactly, is being investigated. That news followed the revelation that the relationship between Tether – which operates the dollar-linked token USDT – and its auditor, Friedman, had “dissolved.”

In its response to the FOIA request, dated June 5, the CFTC wrote that it found “thousands of responsive records, all of which are exempt from the FOIA’s disclosure requirement,” going on to cite a number of exemptions in denying the request, including one commonly applied to law enforcement investigations.

“Some records are exempt from disclosure under FOIA Exemption 7(A), 5 U.S.C. § 552(b)(7)(A), because disclosure of that material could reasonably be expected to interfere with the conduct of the Commission’s law enforcement activities,” the letter stated.

The letter contained another exemption citation aimed at protecting the confidentiality of sources, noting:

“Some records were obtained on the condition that the agency keep the source of the information confidential. Those records are exempt from disclosure under FOIA Exemption 7(0), 5 U.S.C. § 552(b)(7)(D). That exemption is intended to ensure that “confidential sources are not lost because of retaliation against the sources for past disclosures or because of the sources’ fear of future disclosures.”

“We routinely receive legal process/inquiries from law enforcement agents and regulators conducting investigations, and it is our policy not to comment on the specifics of any such requests,” Bitfinex’s head of marketing, Kasper Rasmussen, told CoinDesk by email.

When reached, a representative for the CFTC declined to comment, adding that it could not confirm or deny the existence of any investigations.

FOIA image via Shutterstock