Shares of Upstart Holdings Inc. /zigman2/quotes/223096209/composite UPST -12.32% are off 3.6% in Monday morning trading after Bank of America analyst Nat Schindler downgraded the stock two notches, to underperform from buy, writing that he sees "little room for upside" with shares up roughly 800% on the year. The S&P 500 /zigman2/quotes/210599714/realtime SPX -1.18% has gained about 19% so far in 2021. Schindler wrote that Upstart sees opportunity in the auto-lending market after having success with its artificial-intelligence-driven personal-loan business, though this new market comes with its own challenges. "Although auto loans represent a much larger [total addressable market], we also highlight the higher barriers to entry with more competitors and established, well-capitalized institutions," Schindler wrote. Upstart's current valuation embeds "premature optimism on Upstart's ability to take material shares in the auto-lending space," he continued. Schindler raised his price objective to $300 from $200 in his note to clients. Shares recently changed hands near $375.