** Shares of cryptocurrency and blockchain-related companies fall premarket
** Safe-haven U.S. dollar firms after breakdown in U.S.-Iran peace talks
** Bitcoin BTC=, the world's biggest cryptocurrency, down 0.9% at $70,737.47, while Ether ETH= falls 1.4% to $2,183.78
** Crypto exchange Coinbase Global COIN.O down 2.7%
** Crypto miners: Riot Platforms Inc RIOT.O and MARA Holdings MARA.O fall more than 3.5%, Hut 8 HUT.O and Bit Digital BTBT.O down nearly 3%
** BTC buyer Strategy MSTR.O declines 2.8%
** BTC mining equipment company Canaan Inc CAN.O down 2.3%
** ProShares Bitcoin Strategy ETF BITO.P falls 3.4%
** iShares Bitcoin Trust ETF IBIT.O down 3.3%
** As of Sunday, BTC down 18.6% YTD, while Ether is down 25.6%
(Reporting by Utkarsh Hathi)
((utkarshtushar.hathi@thomsonreuters.com))