On Wednesday evening, Musk sent out the first email to employees about "difficult times ahead" and the end of remote working unless he approved it, according to Bloomberg. The new rules were enacted immediately, requiring employees to be in the office for at least 40 hours per week. 

Musk's leadership is in the second week. Last week, he fired half the workforce, or about 3,700 jobs, to drive down costs following his $44 billion acquisition. The billionaire has launched an $8 subscription for Twitter Blue and attached user verification to it to drive higher revenues. He told employees his goal is for subscriptions to make up at least half of Twitter's revenue. 

The move to a subscription model comes as advertisers, including General Mills Inc., Pfizer Inc., Mondelez International Inc., and General Motors Co., have paused their advertising spending on the social media platform. Musk tweeted last Friday there has been a "massive drop in revenue." 

On Wednesday, market research firm Insider Intelligence slashed its annual revenue outlook for the company by 40%.