TL;DR

The race to develop AI products is pushing US tech startups to embrace 996 culture — working 9am to 9pm, six days a week. While founders argue it’s necessary to stay competitive, research shows productivity drops sharply beyond 40 hours, with one study finding almost no output difference between 50 and 70 hours.

70-Hour Weeks as a Selling Point

New York AI startup Rilla is upfront about its expectations: job ads warn applicants not to apply unless they’re “excited about working ~70 hrs/week.” The company, which sells AI monitoring systems for sales representatives, has become a poster child for 996 culture in the US tech sector.

Will Gao, Rilla’s head of growth, says the company seeks “people who are like Olympian athletes” and insists employees don’t find the hours gruelling. Browser-Use co-founder Magnus Müller, building AI tools for web browsers from a Silicon Valley “hacker house,” takes a similar view: anyone who wants a 40-hour week is unlikely to fit in.

Driven by Competition, Not Evidence

The pressure comes from the AI industry’s speed. “It’s those that have some funding from venture capitalists, that are in a race to develop their products and get them out to market before someone else beats them to it,” says recruitment expert Adrian Kinnersley.

But the evidence doesn’t support the approach. Michigan State University research found that an employee working 70 hours produces almost no more output than one working 50 hours. A WHO/ILO analysis concluded that working 55+ hours a week increased the risk of death from heart disease by 17% and stroke by 35%.

UK Parallels and Pushback

The trend echoes patterns in UK corporate law and investment banking, where 12-hour days and 65 to 100-hour weeks during major deals are common. UK law allows workers to opt out of the 48-hour weekly limit, making 996-style arrangements legal with consent.

Venture capitalist Deedy Das of Menlo Ventures calls excessive hours “the most common mistake young entrepreneurs make,” noting that experienced workers “can actually work far less and achieve much more because they know what they’re doing.” The CIPD’s Ben Wilmott is direct: “There doesn’t seem to be any correlation at all between working long hours and productivity.”