The CEO of Trump Media urged leading House committee chairmen to investigate eight financial firms over concerns of potentially illicit short selling of DJT, whose majority shareholder is former President Donald Trump.

“I believe quick action is necessary to protect retail shareholders, identify wrongdoers, and determine whether any laws including [Racketeer Influenced and Corrupt Organizations Act] statutes and tax evasion laws have been violated,” wrote CEO Devin Nunes, who on April 24 first asked top House Republicans to probe short selling of Trump Media stock.

Nunes, in a letter dated Wednesday, wrote that the committees should seek documents and testimony from the eight firms that he named: Apex Clearing, Clear Street, Cobra Trading, Cowen and Company, Curvature Securities, StoneX Securities, TradePro and Velocity Clearing.

A spokesperson for Clear Street declined to comment on Nunes’ letter. CNBC has requested comment from the other companies named in the letter.

Nunes’ new letter escalates his efforts to thwart short selling of the Truth Social app owner’s shares by encouraging shareholders to block their stock from being used for such trades, and by asking the Nasdaq Stock Market and the House to probe potentially illegal “naked” short selling.

Naked short sellers, unlike conventional short sellers, do not first borrow a company’s stock to sell for such trades, which act as bets that the share price will fall.

Nunes has suggested that the sharp fall of Trump Media’s share price since the stock began public trading on March 26 is the result of naked short sales, not a belief that the company’s meager revenue of just $4.1 million last year does not come close to justifying a market capitalization of more than $6 billion.

DJT shares were trading 6% higher early Thursday at $47.84 per share, which is 32% lower than its opening price on March 26.

Much of Donald Trump’s net worth is tied up in his 65% stake in Trump Media, but he is currently barred from selling the shares that are now worth more than $5 billion until September due to a provision in the merger with a shell company that took the firm public.

Trump, who is the presumptive Republican presidential nominee, faces pending civil legal judgments of more than $500 million.

“Based on factors including the volume and price of purportedly available ‘locates,’ [Trump Media] has identified ongoing anomalies in DJT trading,” Nunes wrote the House Judiciary, Ways and Means, Financial Services, and Oversight and Reform chairmen in his new letter.

“To assist in determining whether intra-day short sales of DJT are being approved in violation of [Securities and Exchange Commission] rules, we would encourage you to seek documents and testimony from firms (including several Depository Trust Company members) that facilitate short sales,” Nunes wrote in the letter, which was disclosed Thursday by Trump Media in an SEC filing.

“In addition to asking for records and information regarding trading in DJT, relevant documents include compliance policies — including any policies that condone the application of a ‘multiplier’ to facilitate the lending of more shares than are actually available,” wrote Nunes, who is a former Republican congressman from California.

Nunes, in the letter, cited the fact that DJT has continuously remained on Nasdaq’s Reg SHO Threshold List since April 2, 2024.

“An appearance on the threshold list results from persistent settlement failures, and triggers … heightened responsibilities for market participants,” he wrote. “For threshold securities such as DJT, SEC guidance clearly states that the only way to establish ‘reasonable grounds’ for short sales is if the broker-dealer pre-borrows the securities; moreover, ‘a broker-dealer may not re-apply a locate for intra-day buy to cover trades.'”

But the SEC’s website notes that a failure to deliver shares as part of a short sale trade, which can land a company on the Reg SHO threshold list, does not necessarily reflect improper trading activity such as naked short selling.

“There are many justifiable reasons why broker-dealers do not or cannot deliver securities on the settlement date,” the website says about Regulation SHO.

CNBC has requested comment from the House committee chairmen about Nunes’ letter.

In a letter last month to Nasdaq’s CEO about potential market manipulation of Trump Media shares by naked short selling, Nunes named four market-making companies as being responsible for more than 60% “of the extraordinary volume of DJT shares trade.”

Nunes did not accuse those four companies of wrongdoing. But his use of their names drew a blistering reply from one of them: Citadel Securities, whose founder Ken Griffin is a major Republican donor.

“Devin Nunes is the proverbial loser who tries to blame ‘naked short selling’ for his falling stock price,” a Citadel Securities spokesperson told CNBC at the time.

“Nunes is exactly the type of person Donald Trump would have fired on [The] Apprentice,” the spokesperson said, referring to Trump’s former business competition reality TV show. “If he [Nunes] worked for Citadel Securities, we would fire him, as ability and integrity are at the center of everything we do.”

A spokeswoman for Trump Media in response to that at the time said, “Citadel Securities, a corporate behemoth that has been fined and censured for an incredibly wide range of offenses including issues related to naked short selling, and is world famous for screwing over everyday retail investors at the behest of other corporations, is the last company on earth that should lecture anyone on ‘integrity.’ “

– Additional reporting by CNBC’s Kevin Breuninger