Bitcoin is up almost 40% since the beginning of the month and new year, but retail traders are still sitting on the sidelines, according to Mizuho. That’s according to a survey it conducted of Coinbase customers, and it could lead to big declines in the crypto exchange’s share price, the firm said in a note Tuesday. Mizuho polled more than 170 Coinbase retail customers and asked about their trading behavior in December and January. “Retail trading is COIN’s bread and butter, as it accounted for 83% of total revenue in 2021,” Mizuho analyst Dan Dolev said in the note. “Our survey, coupled with disappointing market share data and potential signs of take rate pressure in 4Q, may all mean that more headwinds are brewing for 2023 revenue.” Mizuho reiterated its underperform rating on Coinbase and said it sees potential downside of about 45% for the shares. The firm’s survey also showed that nearly 90% of traders who were inactive in December – the month following the collapse of FTX , which rocked the confidence of retail and institutional, new and seasoned crypto investors alike – have remained inactive in January. The survey also found that about a third of investors who indicated they traded crypto through the month of December stopped trading in January, despite the price rally in the new year. This month’s roughly 40% bounce in bitcoin hasn’t led to share gains for Coinbase, Dolev said, which could be further evidence of retail fatigue. “We measured COIN’s volumes against those of 25 of the largest crypto exchanges. We found that COIN’s share of combined volumes during the rally (e.g. January 9-23) was 5.3%, about in line with levels prior to the rally (e.g. January 1-8),” he said. —CNBC’s Michael Bloom contributed to this report.