** Shares of cryptocurrency and blockchain-related firms fall premarket as bitcoin drops 4% to $29,597.50

** Cryptocurrency miners Riot Blockchain and Marathon Patent Group fall 2.6% and 2.8%, respectively

** MicroStrategy Inc, a BTC buyer and business intelligence software firm, declines 2.7%

** Shares of crypto exchange Coinbase Global tick down 1.4%

** Bitcoin mining machine makers Ebang International and Canaan Inc shed 0.9% and 0.7%, respectively

** YTD, BTC has risen ~2.2%

(Reporting by Aaron Saldanha) ((Aaron.Saldanha@thomsonreuters.com; +91 9810644993; Reuters Messaging: Aaron.Saldanha@thomsonreuters.com@reuters.net))