Poolin, once among the largest mining pools, is filing for bankruptcy, auctioning its last Texas sites to repay 11,700 users still holding IOUs from withdrawals frozen back in 2022. A pool is only a coordinator; the hashing was never really theirs. Once a custodian starts issuing IOUs instead of paying out, it has become a bank, and banks can fail. Pooling hashpower was supposed to reduce variance, not add a trusted third party to the payout. Apparently it did both.