Coinbase Global (NASDAQ:COIN) stock is dropping 3.8% in Wednesday premarket trading after Atlantic Equities analyst Simon Clinch downgraded the cryptocurrency exchange company to Neutral from Overweight on concerns over its ability to attract talent in the longer term.The analyst also expressed concern about the spread of misinformation over the company's financial strength and consumer asset protections."Additionally, our hopes for some stabilization in crypto prices and volumes have been dashed, with both tracking much weaker than expected," Clinch wrote in a note to clients.Noting the downside risk of a prolonged and more severe crypto winter, Atlantic Equities reduces base case expectations. Net revenue estimate is cut by 10% for FY22 and by more than 50% in FY23 and FY24.In May, Seeking Alpha's Quant system flashed red on Coinbase (COIN), warning that the stock is at high risk of performing poorly. It puts a Strong Sell rating on the stock. Meanwhile, SA Authors' average rating of Neutral aligns with Clinch's rating.SA contributor Dilantha De Silva sees Coinbase (COIN) has a risky short-term bet but an attractive stock for a long-term investor.