Poolin Technology Pte. Ltd., the Singapore-based company that once operated one of Bitcoin’s largest mining pools, filed for Chapter 11 bankruptcy on July 22 as it moves to sell remaining assets and wind down operations under court supervision.

The filing in the U.S. Bankruptcy Court for the District of New Jersey covers Poolin and two U.S. affiliates, Lonestar Dream Inc. and Lonestar Taproot LLC. Court documents list prepetition obligations of more than $100 million and assets of less than $10 million.

The largest single liability in the case is tied to unpaid user balances. About 11,700 wallet holders are owed $163.7 million, according to a court declaration from Chief Restructuring Officer Michael DuFrayne. Those debts stem from IOU tokens Poolin issued after freezing withdrawals for Poolin Wallet and Pool Account users in September 2022.

Poolin was founded in Beijing in 2017 by Zhibiao “Kevin” Pan, Fa Zhu, and Tianzhao Li, all veterans of mining-hardware maker Bitmain. The company grew into one of the world’s biggest Bitcoin mining pools and, at its peak, controlled nearly a fifth of the network’s global hashrate. By the time of its bankruptcy filing, however, Poolin’s share of Bitcoin mining activity had already dwindled sharply, and the company had largely faded from the ranks of top-tier pools—a decline that the Chapter 11 process now formalizes.

A mining pool allows individual Bitcoin miners to combine hashrate—the computing power used to solve cryptographic puzzles and add new blocks to the blockchain—so participants can earn rewards more consistently than they could by mining alone.

Poolin later expanded beyond mining pool services into crypto lending and interest-bearing accounts through a product called Poolin Wallet. Its financial problems became public in September 2022, when the company halted withdrawals for Poolin Wallet and Pool Account users. At the time, Poolin said it was “facing some liquidity issues,” citing a surge in withdrawal demand during the broader crypto market crash that year. That crash also triggered failures at other crypto lending and trading platforms, including Celsius Network, BlockFi, and Voyager Digital, several of which similarly froze customer withdrawals before entering bankruptcy proceedings.

Instead of repaying customers in full, Poolin issued IOU tokens as placeholders for Bitcoin balances. Those obligations were not repaid and now represent the biggest claim in the bankruptcy proceedings.

Poolin’s Texas mining and hosting business, operated through Lonestar Dream, shut down entirely on July 10, and the company says it does not plan to restart those operations.

To recover funds, Poolin is seeking to auction two West Texas mining sites. Thor CALAP LLC has submitted a $52 million stalking-horse bid, which sets the minimum price that competing bidders must exceed in a court-supervised sale. The bid applies to the physical mining infrastructure and does not cover the frozen wallet balances. The gap between the stalking-horse bid and the $163.7 million owed to wallet holders means unsecured creditors are likely to face substantial shortfalls unless higher bids emerge at auction.

The Texas units had already recorded about $45.9 million in losses since opening, along with another $8.8 million in losses from selling equipment at discounted prices between fiscal 2023 and 2025.

Any recovery for the roughly 11,700 IOU holders now depends largely on the proceeds from the Texas asset auction, more than three years after Poolin first froze withdrawals.