TMTPOST--UBS Group has downgraded Tesla's stock, citing worries that the electric carmaker's shares have surged "too much, too soon" due to optimism surrounding its artificial intelligence initiatives. In a note, UBS analysts including Joseph Spak downgraded the rating to sell from neutral, saying, "If market enthusiasm for AI diminishes, this may impact Tesla’s multiple." The downgrade is justified by "the lack of visibility and the risk that growth opportunities may take longer to materialize (or may not materialize at all)," they wrote, pointing out that the stock is trading at more than 80 times the one-year forward earnings estimate. UBS's action reflects growing concerns over the valuations of AI-related companies, highlighted by a recent selloff in Big Tech shares. Tesla is also facing a challenging outlook for electric cars, with declining sales and profits.