** Shares of cryptocurrency and blockchain-related companies down premarket, hurt by weakness in bitcoin
** Bitcoin BTC=, world's biggest cryptocurrency, falls ~2.3%, while Ether ETH= drops ~1.1%
** Crypto exchange Coinbase Global COIN.O down ~1.9%, U.S.-listed shares of blockchain farm operator Bitfarms Ltd BITF.O down ~1.8%
** Crypto miners Riot Platforms Inc RIOT.O, Hut 8 Mining HUT.O and Marathon Digital MARA.O down between ~2.5% and ~3.6%