Investors came in to Upstart's (UPST 5.53%) first-quarter earnings report hoping the company would maintain its momentum from the end of last year.Its growth has accelerated thanks to a new artificial intelligence (AI) model, Model 18 or M18, that has significantly improved its conversion rate thanks to an even broader prediction set that includes approximately 1 million predictions per applicant, or six times its prior model.With those tailwinds behind it, Upstart's results in Q1 did not disappoint. Revenu ...