Crypto liquidity firm BlockFills suspended withdrawals after $75 million losses and CEO Nicholas Hammer stepped down.  Blockfills is a Chicago-based crypto liquidity provider and lender that primarily serves institutional clients such as hedge funds, asset managers, and high-net-worth trading firms.Leadership exits and sale efforts signal financial distress at a major institutional trading firm.Withdrawal freezes raise solvency concerns and counterparty risk across crypto markets.Institutional crypto lender ...