Trevor Milton, Nikola’s founder and executive chairman, also responded to the report via a tweet, calling it a “hit job” and “lies.” He promised in a subsequent tweet to provide a detailed report to address what he called “one sided false claims”

Nikola declined 11% to $37.75 at 1:50 p.m. in New York after earlier trading as low as $37.05. The shares have risen about 7% since the company went public through a reverse merger with a blank-check company on June 4. At one point, Nikola shares had ballooned to almost $80 a share, giving it a market capitalization greater than Ford Motor Co. despite not generating any meaningful revenue.

Read more: Nikola Founder Exaggerated the Capability of Debut Truck

In June, Bloomberg News reported that, according to people familiar with the matter, Milton had exaggerated the capabilities of its debut big rig during an unveiling event in December 2016. Hindenburg refers to that story in a portion of its report.

The short report followed news on Tuesday that General Motors Co. took a $2 billion equity stake in Nikola. GM agreed to manufacture and supply key components for Nikola’s debut electric pickup, called the Badger. The Detroit giant also will provide fuel-cell and battery technology for Nikola’s semi trucks, which are due to be built at a factory under construction in Coolidge, Arizona.

GM didn’t put any cash into Nikola — it will simply license technology to the company and manufacture its product. But allegations about Nikola could cast a pall over the deal and become a black eye for GM, whose shares fell as much as 4.7% on Thursday.

Read More: Nikola and Rivian’s Appetite for Risk Is Prize for GM, Ford

In response to Hindenburg’s claims, GM expressed confidence in Nikola’s ability to create value. “We stand by the statements we made in announcing the relationship,” spokesman Jim Cain said in an email.

CNH Industrial NV’s Iveco unit held a 6.7% stake in Nikola as of June 3 and has an agreement to build one of Nikola’s battery-electric semis at a facility in Germany. CNH shares fell as much as 3.2% during European trading hours on Thursday. The company didn’t immediately reply to a request for comment.

Earlier this year, Hindenburg Research called out companies including SCWorx Corp. and Predictive Technology Group for making claims tied to the coronavirus. Trading in both companies’ shares was later temporarily suspended by the U.S. Securities and Exchange Commission. In 2016, Hindenburg submitted an SEC whistleblower complaint tied to RD Legal, a hedge fund that was later sued by the agency for allegedly making material misstatements to its investors.