President Donald Trump has thrown his support behind crypto firms in their high-stakes battle with U.S. banks over whether they can offer interest-like returns on stablecoins.

Trump, in a social media post late Tuesday, ratcheted up pressure on banks to relent on the stablecoin yield issue.

That’s the key point of contention holding up passage in Congress of the Clarity Act, which is a companion bill to the Genius Act approved last year, setting up a framework for regulated stablecoins.

“The Genius Act is being threatened and undermined by the Banks, and that is unacceptable,” Trump said in his post. “They need to make a good deal with the Crypto Industry because that’s what’s in best interest of the American People.”

Coinbase shares surged as much as 13% in early trading Wednesday, while shares of JPMorgan Chase and Bank of America fell less than 1%.

While Trump’s decision to back the crypto industry could sway members of his Republican Party in the GOP-led Congress, it’s unclear whether his support is enough to ensure the bill’s passage. The move also raises fresh questions over potential conflict of interests, as the president and his family have reportedly generated hundreds of millions of dollars in wealth from interests in firms including the crypto platform World Liberty Financial.

The dispute between the industries centers on whether crypto firms like Coinbase can offer yields on stablecoins. While crypto companies see it as a consumer-friendly innovation that will let people earn money on their idle funds, banks have warned that the competing product could siphon trillions of dollars from their industry.

Executives from JPMorgan and Bank of America, the two largest American lenders by assets, have cited a Treasury study that indicated that banks could lose up to $6.6 trillion in deposits if stablecoins offered a yield.

That could destabilize some banks, especially smaller ones, and remove a source of funding for loans to businesses across the country.

Allowing the less-regulated crypto industry to behave like quasi-banks could heighten systemic risk, banks argue. Crypto firms say that the risks are contained and that stablecoins backed by Treasuries will boost demand for U.S. debt.

“It can’t be, you have these people doing one thing without any regulation, and these people doing another,” JPMorgan CEO Jamie Dimon told CNBC’s Leslie Picker on Monday. “If you do that, the public will pay. It will get bad.”

In recent months, the president has hosted a series of White House meetings between the two sides in hopes of brokering a deal, but the banks haven’t relented, according to people with knowledge of the gatherings.

Now, he is explicitly putting his weight behind crypto.

“Americans should earn money on their money,” Trump said in the post. “This industry cannot be taken from the People of America when it is so close to becoming truly successful.”

That phrasing is similar to language that Coinbase CEO Brian Armstrong has used in interviews. Coinbase is the largest U.S. crypto platform and provides yield to members through what critics in the banking industry call a “loophole” in current regulations.

Armstrong, seen by banks as their main adversary in this dispute, met with Trump at the White House shortly before the president’s social media post Tuesday, according to a person with knowledge of the meeting. That detail was reported earlier by Politico.

Both banks and crypto firms have reasons to support passage of the Clarity Act, but it’s unclear whether that will happen, given the disagreement. Earlier this year, Trump attempted to pressure banks to cap credit card interest rates, but the industry had enough support among both Republicans and Democrats to ward off that threat.

Tensions between Armstrong and banking CEOs have climbed since the Coinbase CEO publicly called out banks for their opposition to stablecoin yields.

In January, Dimon reportedly told Armstrong he was “full of s–t” during a chance interaction at the World Economic Forum in Davos, Switzerland.