Leading cryptocurrency exchange Poloniex will stop offering nine coins to United States-based customers due to uncertain regulations, according to a blog post published on May 16.

Starting from May 29, Poloniex will stop offering trading in Ardor (ARDR), Bytecoin (BCN), Decred (DCR), GameCredits (GAME), Gas (GAS), Lisk (LSK), Nxt (NXT), Omni Layer (OMNI), and Augur (REP) for its customers in the U.S. Trading with the aforementioned assets will remain available for the exchange’s customers outside the U.S.

Poloniex said that the decision was motivated by the uncertain regulatory environment in the country. “Specifically, it is not possible to be certain whether U.S. regulators will consider these assets to be securities,” the exchange states.

The legal status of cryptocurrency remains uncertain in the U.S. As previously reported, the U.S. Securities and Exchange Commission’s (SEC) “crypto czar” Valerie Szczepanik said that platforms seeking to list initial exchange offering (IEO) tokens for a fee could find themselves in regulatory trouble. “If they are not registered they will find themselves in trouble in the U.S., if they have a U.S. issuer or U.S. buyers, if they are operating on the U.S. market,” Szczepanik said.

In early April, the SEC published a framework, developed by Szczepanik and another commissioner Bill Hinman, to help market participants ascertain whether or not a digital asset is deemed to be an investment contract, and therefore a security.

SEC Chairman Jay Clayton and Commodities Futures Trading Commission (CFTC) Chairman J. Christopher Giancarlo noted the importance of the agencies becoming literate in digital assets and blockchain technology earlier this month. Giancarlo added that the CFTC should “be able to conduct independent market data analysis across different data sources, including decentralized blockchains and networks, without being reliant on self-regulatory organizations and market intermediaries.”