Security experts believe hundreds of millions of dollars worth of cryptocurrency were stolen from decentralized finance platform Drift on Wednesday after the site confirmed it was experiencing a cyberattack. 

The Drift Protocol published multiple notices on Wednesday afternoon saying it is “experiencing an active attack” and that deposits as well as withdrawals are being suspended. 

“We are coordinating with multiple security firms, bridges, and exchanges to contain the incident. This is not an April Fools joke,” the company said. 

Officials at Drift Protocol initially said they were observing unusual activity that required an investigation, urging customers not to deposit any funds and to proceed with caution. 

Multiple blockchain security firms said the losses appeared to be steep. Experts at PeckShield told Recorded Future News that they exceeded $285 million while other firms said at least $130 million worth of cryptocurrency was seen being siphoned from the platform. Drift did not respond to requests for comment about how much was taken.

Experts said the hacker behind the incident is converting the funds repeatedly into other coins. Crypto sleuths are still debating how the threat actor was able to pull off the heist. 

Founded in 2021, the Drift Protocol is built on the Solana blockchain and offers borrowing, lending, perpetual trading and spot trading. Cofounder Cindy Leow told Fortune in 2024 that they wanted to make Drift the “Robinhood of crypto.”

On its website, the company links to multiple code audits it underwent in 2023 and 2024. 

This would be the largest crypto theft of the year following incidents involving $26 million and $40 million worth of cryptocurrency earlier this year. Blockchain security firm Chainalysis tracked $3.4 billion in losses last year from crypto thefts, including $1.5 billion stolen from Dubai-based platform Bybit.