** Shares of cryptocurrency- and blockchain-related companies down premarket, on weakness in bitcoin
** Bitcoin BTC=, the world's biggest cryptocurrency, is down ~2.1%, while ether ETH= down ~5.5%
** Crypto exchange Coinbase Global COIN.O down ~0.6%, U.S.-listed shares of blockchain farm operator Bitfarms Ltd BITF.O down ~1%
** Crypto miners Riot Platforms Inc RIOT.O, Hut 8 Mining HUT.O and Marathon Digital MARA.O down between ~1% and ~1.3%
(Reporting by Jaiveer Singh Shekhawat in Bengaluru)