Tesla boss Elon Musk has had enough of employees working from home. In a circular email, he urges his people to come to the office at least 40 hours a week – or to leave the company.

Everyone back to the office or permanent home office? This is a question many large companies are asking themselves, and the answer often lies in a compromise that allows employees to do both on a daily basis. However, anyone who has Elon Musk as boss cannot count on that much flexibility.

In an email to his executives, the boss of Tesla and SpaceX made it more than clear what he thinks of working from home: nothing. “Remote work is no longer acceptable,” says the subject of the email that circulated on Twitter and whose authenticity Tesla employees US media confirmed.

Every employee must be in the office at least 40 hours a week, Musk wrote, “or leave Tesla.” Musk wrote to his senior staff that this is still less than what Tesla is asking of a normal factory worker. He only accepts home office for work that goes beyond these 40 hours. Exceptions for individual special cases are to be approved by him personally.

“If you don’t show up…”

The topic is obviously burning under Musk’s nails, because a little later he sent a second email to everyone (subject: “To be super clear”). In it, Musk writes: “Everyone at Tesla has to spend at least 40 hours a week in the office.” And by “office” he means the place where the colleagues are actually, “and not some remote pseudo-office,” says Musk. “If you don’t show up, we’ll assume you’ve resigned.”

The more important the position in the company, the more visible the presence of the individual has to be, Musk explains his work ethos. He himself spent a lot of time in the factory so that the local colleagues could see him working next to them. “If I hadn’t done that, Tesla would have been broke a long time ago.” Of course there are companies where that isn’t necessary, Musk adds. “But when was the last time they released a great product?”

According to the Washington Post, Musk also sent a letter similar to the one to the Tesla employees to the employees of his space company SpaceX. Musk has not officially commented on his leaked emails. On Twitter, however, he responded to a post sharing the email and asked what he said to people who think office work is an antiquated concept. Musk’s response: “They should pretend to work somewhere else.”

There is a home office culture on Twitter

So Musk’s uncompromising stance on the home office is clear. Other US companies, on the other hand, are pursuing completely different strategies. At the end of April, the announcement by Airbnb boss Brian Chesky caused a stir that his 5,000 employees could work from wherever they wanted in the future – and without a drop in salary. He understands the concern of not knowing how well the employees work when they are not in the office, Chesky wrote in an email to the employees. But: “For me, the answer is simple: I trust you – and flexibility only works if you trust the people in your team.” In ten years, this way of working will dominate, predicted Chesky.

Twitter boss Parag Agrawal also wrote to his employees in March that the offices were open again, but that everyone could decide for themselves whether to go. “Wherever you feel most productive and creative, that’s where you’re going to work, and that includes permanent working from home,” Agrawal said. Shortly thereafter, Musk announced that he wanted to acquire Twitter for $44 billion.