Ex-Tesla and SpaceX managers say Elon Musk's commitment to his companies is often inspirational but can also turn toxic

• Some of Elon Musk's former colleagues have highlighted his loyalty to his firms, per the NYT.
• Ex-SpaceX and Tesla workers said his commitment was often inspirational.

Former Tesla and SpaceX managers have discussed Elon Musk's loyalty to his businesses, which they said was often inspirational but could also become toxic.

The New York Times reported the news on Monday.

The comments came after Musk gave Twitter employees an ultimatum last week: work "extremely hardcore" or resign. Musk's strict work ethic and aggressive goals have also been evident at some of his other companies.

In the interview with the Times, three former SpaceX and Tesla managers highlighted Musk's full commitment but said it could also create a culture of fear and scapegoating.

Musk doesn't hold back from discussing how his companies could fail. In a recent Twitter all-hands meeting, Musk said he sold Tesla stock to "save" the platform and emphasized keeping the site "alive."

David Deak, a former senior Tesla engineering manager, told The Times that Musk "thrives in existential circumstances," which he uses to try to "light the fire under everybody."

Musk's management style was "good start-up and growth strategy, but it is not good for building a stable company," Deak said.

Deak described the billionaire's leadership at Twitter as "typical Elon."

Two former Tesla executives told The Times that Musk's austerity mixed with an atmosphere of crisis allows him to carry out mass layoffs, fire senior staff, and make big changes to the company.

Deak, Tesla, and SpaceX didn't immediately respond to Insider's request for comment.

Last year, Musk told SpaceX employees a lack of progress on Starship engines created a "risk of bankruptcy," per a memo obtained by CNBC. He also urged Tesla workers in an email seen by Reuters to "go super hardcore" to finish the quarter strong.

Since his takeover of Twitter on October 27, Musk has laid off thousands of employees at Twitter. He's also clamped down on remote work.