Major cryptocurrencies took a nosedive on Wednesday evening amid concerns about the possible approval of a spot Bitcoin ETF. What Happened: Data from Coinglass shows that in the past 24 hours, over $600 million worth of cryptocurrency longs, (which are bets on higher prices with borrowed money) were liquidated. Bitcoin experienced a rapid drop from approximately $45,000 to a low of $40,000 early on Wednesday. The decline coincided with the release of a report by Markus Thielen, published by Singapore-based digital asset firm Matrixport, predicting that the Securities and Exchange Commission (S…