Ether-linked stocks jump as cryptocurrency hits seven-month high

** Shares of ether-linked companies rise premarket

** Cryptocurrency ether ETH= hits seven-month high; last up 1.64% at $3,887.13

** Blockchain-focused companies Gamesquare Holdings GAME.O up 6.2%, BTCS BTCS.O rises 7.7%, Bitmine Immersion Technologies BMNR.A up 4.1%

** Sharplink Gaming SBET.O jumps 8.2%, while Bit Digital BTBT.O rises 5.4%

** iShares Ethereum Trust ETF ETHA.O jumps 7.1%