(Bloomberg) — Nikola Corp. shares dropped as much as 18% after the company issued a blanket denial of allegations made in a short-seller report without offering any specifics to refute allegations it lied about its technology and staged events.The electric-truck startup said allegations made by Hindenburg Research are false but did not provide evidence to refute specific claims in the report. Chairman and founder Trevor Milton had vowed earlier Friday to issue a detailed rebuttal after “working through the night.”Nikola instead hired law firm Kirkland & Ellis to consider its legal options and said it plans to bring unspecified documentation to the attention of the Securities and Exchange Commission.“We have nothing to hide and will refute these allegations,” the company said Friday in a statement. “To be clear, this was not a research report and it is not accurate. This was a hit job for short sale profit driven by greed.”Milton said in a tweet Friday he wouldn’t make any further comments about the allegations on the advice of counsel. In reference to earlier pledges to provide a “detail report” to address Hindenburg’s claims, he hinted in another tweet that might take time.“This document had to be prepared well with the SEC in mind. It will be released as soon as they give me the green light,” he said.Although Milton didn’t explain from whom he was awaiting a “green light,” he may have been referring to his lawyers. The SEC doesn’t generally sign off on company disclosures before they are filed and made available via the regulator’s public filing database.Judy Burns, an SEC spokeswoman, didn’t immediately respond to a request for comment.Gain Wiped OutHidenburg Research’s founder, Nathan Anderson, said he welcomed Nikola’s pledge to petition securities regulators. “We are pleased that Nikola is engaging with the SEC and we are not surprised that Trevor Milton is not commenting further on advice of counsel,” he said in a phone call.Nikola’s reply came in an effort to reassure investors after the report — issued Thursday by a firm that may stand to gain from a decline in the share price — alleged the startup made nonworking products appear as fully functional, staged misleading videos and told “dozens of lies” about its capabilities, partnerships or products.That set off a two-day plunge in the stock that sent it back below the $33.75 close on June 4 when it gained its public listing.Nikola pared an early swoon as low as $30.78 on Friday, trading down 15.8% to $31.62 as of 12:55 p.m. in New York. The share loss gained momentum after another firm that often issues short-selling reports weighed in: Citron Research. It thanked Hindenburg in a tweet, offering to pay for half of any legal expenses incurred.Exaggerated CapabilitiesIn June, Bloomberg News reported that, according to people familiar with the matter, Milton had exaggerated the capabilities of Nikola’s debut big rig during an unveiling event in December 2016. Hindenburg refers to that story in a portion of its report.Nikola was little-known before it went public in early June through a reverse merger with a blank-check company. It’s one of a handful of startups with next-generation auto technology that have attracted interest from so-called special purpose acquisition companies and charmed stock investors. At one point, Nikola shares ballooned to almost $80 a share, giving it a market capitalization greater than Ford Motor Co. despite not generating any meaningful revenue.Its stock rallied anew earlier this week after a surprise announcement Tuesday that General Motors Co. would take a $2 billion equity stake in Nikola. The deal committed GM to manufacturing the startup’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 expressed confidence Thursday in its partner’s ability to create value.(Updates with additional comments from Nikola chairman from fifth paragraph.)For more articles like this, please visit us at bloomberg.comSubscribe now to stay ahead with the most trusted business news source.©2020 Bloomberg L.P.