Bitcoin breaks below $50K as cryptocurrency selloff continues

At its worst levels of about $47K in the pre-dawn hours, bitcoin (BTC-USD) was down more than 25% from its all-time high hit last week amid the Coinbase (COIN) public listing frenzy.There's been a modest bounce since, and bitcoin is currently changing hands at $49.9K.Recent speculative favorites like Dogecoin (DOGE-USD), Filecoin (FIL-USD), Binance Coin (BNB-USD) are faring even worse.The catalyst for the selloff may have been chatter about a sharply higher capital gains tax rate, but the recent crypto furor almost demanded a cool-down period.Checking some blockchain-related companies in the premarket ... Coinbase, Microstrategy (MSTR), Riot Blockchain (RIOT), Marathon Digital (MARA) are all down 2%-3% following far larger tumbles in yesterday's trade.