Coinbase says it's halted Ethereum Classic transactions, withdrawals, and deposits, after a 51% attack on the cryptocurrency led to coin double-spending
Crypto exchange Coinbase has halted all ethereum classic transactions, withdrawals and deposits due to a series of blockchain history reorganizations on the network.
Context & Ripple Effects
Coinbase added Ethereum Classic support only months ago, announcing plans in June 2018 to list the Ethereum fork — so this halt lands on one of its newest assets. The exchange has a track record of freezing markets when integrity is in doubt: it reimbursed customers after the 2017 GDAX Ethereum flash crash that briefly took ETH from $320 to $0.10, and repeatedly suspended trading during the December 2017 traffic crunch.
First-order effects
- ETC holders on Coinbase cannot deposit, withdraw, or trade while the halt stands, and any coins moved in the double-spend are now contested balances the exchange must reconcile.
Second-order effects
- Other exchanges holding ETC face the same reorganization risk and will likely mirror the halt or add confirmations, deepening the liquidity freeze; given the flash-crash reimbursement precedent, Coinbase may face customer-loss claims it has paid out on before.
Third-order effects
- If a 51% attack is cheap enough to execute on a listed asset, exchanges become de facto arbiters of which proof-of-work chains are safe to support — listing and delisting decisions start pricing in attack cost, not just demand.
The trend: Exchange custody is turning blockchain-level attacks into immediate market-access events, forcing platforms to act as the last line of defense for small-hashrate cryptocurrencies.