Security token trading platform Openfinance is threatening to delist all tokens and suspend trading next month unless issuers cough up more funds to cover its costs.

The company has not seen transaction activity on its platform grow quickly enough to cover operating costs, according to an email sent to the alternative trading system’s (ATS) users and shared with CoinDesk on Wednesday.

The email is asking issuers with tokens listed on the site to cover these costs with new contracts. If it doesn’t receive new fees, it will delist all existing tokens on May 21 and suspend trading.

Non-tokenized securities will continue trading, the email said, although it’s not clear how many traditional instruments Openfinance actually lists.

“We have asked the issuers currently listed on the platform to renew their listing agreements and cover a portion of our costs, including through annual listing fees, as are common in large, public markets, where issuers pay exchanges for listing services,” the email said.

A company representative did not immediately respond to a request for comment.

Openfinance launched its ATS in August 2018, allowing accredited investors in the U.S. and investors outside the country to trade and purchase security tokens.

Tokens listed on Openfinance include or at some point included Blockchain Capital’s BCAP token, SPiCE, Current Media’s CRNC token, Lottery.com’s LDCC token and Protos’ PRTS. Openfinance is also supposed to list NBA guard Spencer Dinwiddie’s personal token when it launches.

Openfinance has raised over three rounds from Sharpe Ventures, M25 and Huobi, according to Crunchbase. Its last round saw the company raise $8.6 million.

Kyle Sonlin, CEO of Security Token Market, told CoinDesk that Openfinance closing its security token platform would be “a loss for the industry,” particularly in the U.S.

“It’s worth noting, however, that these security tokens can simply be self-custodied and eventually moved to another platform, which is a testament to the functionality and efficiency of security token technology,” he said.

The securities themselves would not experience any disruption in ownership, the email from Openfinance said. The issuers and their transfer agents will still maintain ownership records. Users can also maintain the tokenized records in their own digital wallets.

The email notes that users could transfer security tokens directly to buyers and sellers. User funds will be maintained at Evolve Bank, an FDIC-insured institution in West Memphis, Arkansas.