Why did Riot Blockchain stock drop today? Year-end pressure on bitcoin

Bitcoin miner Riot Blockchain (NASDAQ:RIOT) shares slide 8.0% in Tuesday trading, its biggest one-day drop since Dec. 3, as bitcoin (BTC-USD) loses 6.7% in the past 24 hours to ~$47.8K. Other bitcoin-mining stocks also felt the pain with Marathon Digital (NASDAQ:MARA) sinking 10%, Hut 8 Mining (NASDAQ:HUT) diving 12%, Bitfarms (NASDAQ:BITF) off 11%, and Greenidge Generation Holdings (NASDAQ:GREE) -9.8%. Some investors may be turning away from speculative investments at year-end in favor of safer havens. The U.S. dollar index rises 0.1% to 96.17. In equities, more defensive sectors like Utilities and Materials are in the green while Information Technology and Communication Services are in the red. Other cryptocurrency-related stocks drop, including Coinbase Global (COIN -6.7%), Silvergate Capital (SI -5.6%), MicroStrategy (MSTR -6.9%), and Galaxy Digital Holdings (OTCPK:BRPHF -5.6%). Earlier, MicroStrategy stock dips as bitcoin falls below key $50K level again.