The US Commodity Futures Trading Commission (CFTC) has refused a Freedom of Information Act (FOIA) for a release of the subpoenas allegedly issued last year to cryptocurrency exchange Bitfinex and token issuer Tether, Coindesk reports Wednesday, June 6.

Bitfinex and Tether share a CEO, Jan Ludovicus van der Velde, and the two entities had created controversy last fall over alleged price manipulation of Tether. The two companies reportedly received subpoenas from US regulators on Dec 6, 2017, with the impetus for the subpoenas still unclear.

Tether has also since been under some scrutiny from the crypto community after they dissolved a relationship with their New York-based auditor before an official audit was released. The “stable-coin” issuers recently minted 250 mln more USDT at the end of May, renewing debate about whether Tether has enough cash reserves to back each token with one US dollar as they advertise.

The June 5 FOIA request, which was initially submitted in February, asked for "subpoenas issued to iFinex inc. also known as Bitfinex and it's [sic] subsidiary companies, as well as subpoenas issued Tether Limited and its subsidiary companies.”

The CFTC’s negative response to the request noted that it had "thousands of responsive records, all of which are exempt from the FOIA's disclosure requirement.”

The letter cited one FOIA exemption that disclosure could impede their law enforcement activities, as well as another that excludes the records on the ground that "confidential sources are not lost because of retaliation against the sources for past disclosures or because of the sources' fear of future disclosures."

In response to Cointelegraph’s request for comment, Kasper Rasmussen, the head of marketing at Bitfinex, provided the following statement:

"We routinely receive legal process from law enforcement agents and regulators conducting investigations. It is our policy not to comment on any such requests."

Tether had not responded to Cointelegraph’s request for comment by press time.