From its name on down, it’s clear that zero-emissions vehicle startup Nikola aims to emulate Tesla’s soaring trajectory. But over the past six months, Nikola’s efforts to follow that blueprint have faced a series of setbacks including fraud allegations, key resignations, and a reported fraud inquiry by federal regulators.

On Monday, the headwinds grew stronger when Nikola announced that General Motors will effectively withdraw from a planned partnership that was announced in September. Investors had seen the deal as a huge win for Nikola, by giving it a massive jolt of credibility.

Under the proposed agreement, GM would have provided battery and fuel-cell technology to Nikola and manufactured Nikola’s planned Badger electric pickup.

In exchange, GM was to take an 11% stake in Nikola, as well as cash payments for its services. The deal would also have given GM a stronger foothold in the emerging zero-emissions vehicle market.

Now, instead, GM will become little more than a supplier to Nikola. Under the revised deal, GM would take no stake in Nikola. Instead, Nikola would pay GM the cost of tailoring GM’s Hydrotec fuel cells to Nikola’s planned freight trucks, and then pay more down the road to buy those fuel cells.

GM will no longer be involved in producing the Badger pickup, which Nikola says it will now cancel entirely.

In a statement, GM patted itself on the back for becoming a supplier to Nikola. But it did not comment about why the initial and much broader agreement was scaled back.

The revised agreement, which must still be finalized, was seen by analysts as negative for Nikola. The startup’s stock crumbled nearly 27% on Monday, to $20.41. That’s a decline of more than 74% from the stock’s peak of $79.73 on June 9, a few days after it went public using what’s known as a SPAC.

Dan Ives, an EV and tech analyst with Wedbush securities, called the announcement of the collapsed GM deal a “clear negative” for Nikola. Emmanuel Rosner, an analyst for Deutsche Bank, described the revised deal as “particularly negative,” because it indicates not just a shift in business strategy but GM’s more fundamental loss of faith in Nikola.

According to Rosner, the elimination of any equity from the deal “makes it clear that after months of additional due diligence, GM is not willing to take any risk on Nikola.” By opting for a cash-only deal, Rosner says, GM is signaling lowered expectations for Nikola’s long-term growth.

The announcement ends months of speculation about the GM-Nikola deal, which was tentatively announced in September. Just days later, a scathing report by short-selling Hindenburg Research alleged a variety of misrepresentations by Nikola of its technology. Most notoriously, Hindenburg claimed that Nikola had faked a promotional video that seemed to show one of its hydrogen-powered semitrucks in motion. Instead, as the company later admitted, the truck had been rolled down a hill.

That unleashed a torrent of fallout. The SEC reportedly started a fraud inquiry, and Nikola founder Trevor Milton, who was directly implicated in Hindenburg’s report, resigned from his role as CEO. And of course, Nikola’s stock slid sharply.

Analysts and investors have since then speculated about whether GM would stick to the deal, given the new evidence of possible bad faith by Nikola, and sharp declines in the current value of GM’s promised stake in the startup. The uncertainty pushed Nikola in October to signal that it could do without the partnership.

There is arguably a narrow silver lining here. The battery-powered, consumer-focused Badger pickup never entirely made strategic sense for Nikola, whose focus has always been on creating long-haul freight trucks fueled by liquid hydrogen. Its elimination may help clarify exactly what Nikola is trying to accomplish, even if it means scaling back the company’s ambitions.

That’s how Nikola is spinning today’s announcement. “We are 100% focused on hitting our development milestones to bring clean hydrogen and battery-electric commercial trucks to market,” Nikola CEO Mark Russell, Milton’s replacement, said in a statement.

But more broadly, the implications are grim. Before the downsized deal was announced, Rosner had pointed out that “Nikola’s outlook [is] highly dependent on its partnerships,” since the company, which has yet to deliver any vehicles, had not convincingly demonstrated a deep well of technical or manufacturing expertise. (Another allegation of the Hindenburg report was that Nikola had overstated claims about its progress on developing its own batteries.)

The timing of the news is particularly bad for one player: Trevor Milton. Despite leaving his CEO post under a cloud, Milton retained ownership of 85.6 million shares of Nikola, or nearly one-fourth of all outstanding shares. Milton was prohibited from selling those shares in the months following Nikola’s September stock market debut, but that prohibition expires tomorrow, Dec. 1—just as his company sheds billions of dollars in value.