** Shares of cryptocurrency and blockchain-related firms fall after bitcoin briefly slides below $40,000 to a 5-month low ** The world"s largest digital asset was last down 2.6% at $40,800 after falling to as low as $39,558.70 on Monday ** Ether also falls as much as 7.2% to $2,926, its lowest since Sept. 30, 2021 ** U.S.-listed miners Bit Digital (BTBT.O), Hut 8 Mining Corp , Marathon Digital Holdings (MARA.O) and Riot Blockchain (RIOT.O) down between 2.3% and 5.4% ** Blockchain farm operator Bitfarms slips 2.8%, while online retailer and blockchain tech investor Overstock.com Inc (OSTK.O) falls 1.9% ** The Nasdaq crypto index (.NCID) which tracks a basket of digital assets, slides 2.9%; ProShares Bitcoin Strategy ETF , the first U.S. bitcoin futures ETF, drops 3.2% ** MicroStrategy (MSTR.O), a BTC buyer and business intelligence software firm, dips 4.6%; crypto exchange Coinbase Global (COIN.O) drops 6.6% ** Bitcoin mining machine makers Ebang International (EBON.O) and Canaan Inc (CAN.O) off 9.3 and 2.5%, respectively ** China-based SOS slumps 4%; crypto bank Silvergate Capital Corp (SI.N) plunges 7.1%