The Fifth Circuit US Court of Appeals looked at the 2018 tweet Musk wrote after a Twitter user pressed him on what he thought of unions amid an organising campaign by the United Auto Workers at Tesla’s Fremont, California plant.

In 2021, the National Labour Relations Board (NLRB) found Musk had violated federal labour laws because of the tweet, which the appeals court upheld on Friday.

The court ordered the removal of the tweet, but so far Musk has been too busy. It reads:

“Nothing stopping Tesla team at our car plant from voting union. Could do so tmrw if they wanted. But why pay union dues & give up stock options for nothing? Our safety is 2X better than when plant was UAW & everybody already gets healthcare.”

In court, Tesla had attempted to counter the NLRB’s ruling by arguing that the tweet could not be seen as a threat since Musk had said Tesla workers could join a union if they wanted.

In its concluding judgment, the Fifth Circuit court wrote that “because stock options are part of Tesla’s employees’ compensation and nothing in the tweet suggested that Tesla would be forced to end stock options or that the UAW would be the cause of giving up stock options, substantial evidence supports the NLRB’s conclusion that the tweet is an implied threat to end stock options as retaliation for unionisation.”

The court also upheld an order that Tesla should re-hire Richard Ortiz, who had been fired for organising the union drive at Tesla’s Fremont, California, factory. The court ruled that he will receive back pay due to his unlawful dismissal.

In a statement, Ortiz said: “This is a happy day where my rights were finally vindicated. I look forward to returning to work at Tesla and working with my co-workers to finish forming a Union.”