Several Wall Street analysts are warning investors to stay away from Coinbase until the cryptocurrency exchange operator works through a “crypto winter,” among other challenges. Coinbase dropped 5% premarket Wednesday after it lost more than $1 billion in the calendar second quarter, while revenue missed analyst estimates. The platform has been contending with a host of challenges including what’s called a “crypto winter” where cryptocurrency prices fall. Coinbase’s stock price cratered in the second quarter as Bitcoin tumbled, and cryptocurrency traders exited the platform. The crypto exchange said assets on its platform slid to $96 billion from $256 billion in the prior quarter. For some analysts, the second quarter report served as a warning that traders should hold off on the stock, and wait and see how it steers through a tough crypto market. Goldman Sachs’ analyst Will Nance…