Solana's largest decentralized finance (DeFi) protocol, Marinade Finance, has blocked users in the United Kingdom from accessing the site due to "compliance concerns" over Financial Conduct Authority (FCA) regulations.

The landing page for users in the U.K. displays a warning message, although it states "users may withdraw liquidity, claim delayed tickets or delay unstake via our SDK."

Marinade is responsible for most of the total value locked (TVL) on the Solana blockchain, with $248 million spread across native and liquid staking products. The amount of assets across the entire Solana blockchain stands at around $350 million, according to DefiLlama.

Marinade currently offers annual yields of 8.15% for native staking and 7.7% for liquid staking, with native staking being rolled out earlier this year.

Orca Finance, Solana's largest decentralized exchange, added geo-blocking for U.K. users. The restrictions against U.K. users appear to be in response to the FCA's new promotions rules, which restrict the marketing of crypto-related products or services.

Centralized crypto businesses like Bybit and Paypal have withdrawn from the U.K. market whilst Binance has temporarily paused new U.K. sign-ups following the release of the FCA's promotions rule. Luno also blocked some customers from investing in crypto.

But geo-restrictions are rare for decentralized protocols, most of which do not require know-your-customer (KYC) checks.

Marinade Finance did not immediately respond to CoinDesk's request for comment.