Tesla has seen better days: Fourth-quarter results were full of bad surprises, the company’s prototype electric SUV has suffered multiple delays, and crashing oil prices weaken the case for electric vehicles. Bank of America’s John Lovallo says Tesla’s stock is overpriced—by a staggering 70 percent. The basic argument goes something like this: Recent sales have been disappointing, and the cost of Elon Musk’s ambition is about to go up as he builds new plants. Judging Tesla by quarterly sales of its luxury Model S is bonkers.