The negotiations between Fisker and a large automaker — reported to be Nissan — over a potential investment and collaboration have been terminated, a development that puts a separate near-term rescue funding effort in danger.

Fisker revealed in a Monday morning regulatory filing that the automaker terminated the negotiations on March 22. It did not explain why. But the company had to keep the negotiations going as part of one of the closing conditions for a potential $150 million convertible note announced last week. Fisker said in the filing that it will ask the unnamed investor to waive the closing condition. The startup’s stock plunged 28% after the stock market opened, halting trading.

It’s the latest in a series of ominous signs for the imperiled EV startup. Fisker has struggled to sell its Ocean SUV in the early going, underperforming its own internal sales goals, as TechCrunch reported in January, forcing a pivot away from a direct sales model. Some of the cars that have been delivered have been affected by a number of quality problems — ones that Fisker has, at times, has struggled to solve, according to internal documents.

In February, Fisker laid of 15% of its staff (around 200 people) and last week reported having just $121 million in the bank. The company has paused production and warned investors it would not survive year without a fresh infusion of cash. Fisker had held talks with other automakers, including Mazda, but only Nissan recently remained at the table.

Fisker said Monday morning that it is evaluating other “strategic alternatives” to the potential tie-up with Nissan, including “in or out of court restructurings, capital markets transactions (subject to market conditions), repurchases, redemptions, exchanges or other refinancings of its existing debt, the potential issuance of equity securities, the potential sale of assets and businesses and/or other strategic transactions and/or other measures.”