Nikola Chairman Trevor Milton Resigns Amid Fraud Claims

The new chairman, Mr. Girsky, has played a critical role in Nikola’s rise to prominence. After leaving the G.M. board in 2016, he started an investment company, VectoIQ, to provide strategic and financial help to automotive technology start-ups. He also created a special purpose acquisition company, or SPAC, that owned nothing but cash and a stock listing. When VectoIQ’s SPAC merged with Nikola in June, Nikola became a publicly traded company and Mr. Girsky joined its board.

Mr. Girsky was also a catalyst for G.M.’s partnership with Nikola. In the past he has said he called on former G.M. engineers to evaluate Nikola’s technology and its business prospects while considering the SPAC merger. When he realized G.M. had developed fuel-cell and battery technology Nikola might be able to use, he put Mr. Milton and G.M.’s chief executive, Mary T. Barra, on contact with each other.

“The initial introductions were made by Steve Girsky,” Ms. Barra said in a conference call to announce the partnership.

The day-to-day running of Nikola is in the hands of Mark Russell, the chief executive, whose ties to Mr. Milton go back several years. Before joining Nikola as president last year, he was chief executive of Worthington Industries, a diverse maker of steel products like tanks for propane, hydrogen, helium and natural gas. Worthington acquired Mr. Milton’s diesel conversion company, dHybrid Systems, in 2014 and also invested in Nikola.

In August, before Nikola’s deal with G.M. was announced, Mr. Russell noted the company’s reliance on suppliers. “We’ve been looking for partners from the beginning,” he told Bloomberg TV. “We are going to be a partner company.”

Before Mr. Milton’s resignation, Sam Abuelsamid, an analyst at Navigant Research who follows developments in electric vehicles, noted that offering bullish forecasts was typical of Silicon Valley start-ups, and that automakers regularly showed early prototypes that are far from production vehicles.

“It certainly seems like Nikola really inherently doesn’t have any technology of note,” he said. “They have a vision and have been going around setting up partnerships with companies that do have the technology and are trying to pull it all together.”