Russian exchanges shouldn’t list investment products related to cryptocurrency prices, the country’s central bank, which regulates the industry, said in an announcement Thursday.

According to a notice published by the Bank of Russia and an explanatory letter, exchange operators should avoid listing securities such as exchange-traded funds that make payments based on the prices of cryptocurrencies, digital assets issued abroad, cryptocurrency price indices, cryptocurrencies, derivatives and securities that issued by cryptocurrency-related funds.

Asset managers should also exclude such securities from mutual fund portfolios and brokers should not offer these securities to qualified investors.

The Bank’s Securities and Commodities Department is the regulator for the Russian stock markets. The ruling is designed to prevent retail investors from gaining access to products they may not understand.

“Cryptocurrencies and digital assets are characterized by high volatility, low transparency of price mechanisms, low liquidity, technological, regulatory and other specific risks,” wrote the bank. “The purchase of linked investment products puts people with no experience or specialist knowledge at high risk of losing money.”

The ban does not include central bank digital currencies that could be issued and registered with the Bank of Russia in accordance with Russian law, or digital assets, the regulator added.