Tesla has an aging vehicle line-up, and its newest North American offering, the Cybertruck, has not impressed reviewers. By its own admission, the company is struggling to scale up the Cybertruck's production as well. Perhaps most worrying for Musk is that Tesla produced almost 47,000 more vehicles during the first quarter than it sold, suggesting that it is beginning to hit real limits on customer demand for its cars. "There must be some kind of supply-demand imbalance here," Cantor said. Tesla has slashed its vehicle prices by thousands of dollars over the past year in order to stimulate demand. Tesla doesn't break out its sales data by region, which is a shame because that could help clarify what is going on. If Tesla's sales are flagging in China and Europe, that could be because consumers are flocking to a new set of EV options. A sales decline in the U.S. would indicate that one of the company's cash cows, the Model Y crossover, is beginning to falter. "If you look at this, you can see where there are yellow flags here," Cantor said. "Tesla can explain it however you want but the numbers speak for themselves.