Wedbush analyst Daniel Ives downgraded Nikola (NKLA) to Underperform from Neutral with a price target of $15, down from $45. The stock closed Wednesday down 26%, or $7.36, to $21.15. The analyst still believes the company’s electric vehicle and hydrogen fuel cell ambitions are attainable in the semi-truck market, but he has “serious concerns that the execution and timing of these ambitious goals stay on track over the coming years.” The Nikola story changes with Trevor Milton gone from the company, Ives tells investors in a research note. Execution risks for Nikola are now “significantly heightened,” says the analyst. Ives thinks the recent questions surrounding the Nikola story “raised by the bears will be a dark cloud over the stock until answered.” In addition, the “eye popping battery innovations” coming out of Tesla (TSLA) “potentially changes the game” with further price parity and “throws a wrench” in Nikola’s return on investment story around hydrogen fuel cell vehicles over the long term, contends Ives.