Bitcoin exchange BitFloor is closing its doors, halting trading and announcing that it will return everyone’s funds. In an announcement on its main site, the company’s founder, Roman Shtylman, says that "due to circumstances outside [BitFloor’s] control" it "must cease all trading operations indefinitely." More specifically, BitFloor says that because its US bank account is closing it won’t be able to provide the same level of dollar deposits and withdrawals that it has been up to this point. The news comes after weeks of DDoS attacks and technical problems at leading exchange Mt. Gox and a roller coaster ride of price fluctuations that saw Bitcoin tank from a high of over $200 back down to a low below $70. The news was reported by The Next Web.

Back in September, BitFloor was hit with a $250,000 theft after an attacker got access to an unencrypted backup set of keys for the exchange’s wallet — the software through which people (and organizations) access and transfer their coins. The exchange managed to get back online within a few weeks, with Shtylman announcing his intention to repay the stolen funds.

Overall, BitFloor is tiny compared to Mt. Gox — it does less than four percent of that exchange’s trading volume — but it represented an important alternative in the highly concentrated market. At this point it’s still unclear what exactly happened with BitFloor’s US bank account that required such a speedy exit, but a Reddit user points out that the exchange is registered with FinCEN — the US Treasury Department’s Financial Crimes Enforcement Network — indicating that everything was seemingly above board with the US government. We’ve reached out to Bitfloor for comment on what precipitated the closure, and will update if and when we hear back.