The era of artificial intelligence on Wall Street, and its impact on workers, has begun.

Big banks including JPMorgan Chase and Goldman Sachs are unveiling plans to reimagine their businesses around AI, technology that allows for the mass production of knowledge work.

That means that even during a blockbuster year for Wall Street as trading and investment banking spins off billions of dollars in excess revenue — not typically a time the industry would be keeping a tight lid on headcount — the companies are hiring fewer people.

JPMorgan said Tuesday in its third-quarter earnings report that while profit jumped 12% from a year earlier to $14.4 billion, headcount rose by just 1%.

The bank’s managers have been told to avoid hiring people as JPMorgan deploys AI across its businesses, CFO Jeremy Barnum told analysts.

JPMorgan is the world’s biggest bank by market cap and a juggernaut across Main Street and Wall Street finance. Last month, CNBC was first to report about JPMorgan’s plans to inject AI into every client and employee experience and every behind-the-scenes process at the bank.

The bank has “a very strong bias against having the reflexive response to any given need to be to hire more people,” Barnum said Tuesday. The bank had 318,153 employees as of September.

JPMorgan CEO Jamie Dimon told Bloomberg this month that AI will eliminate some jobs, but that the company will retrain those impacted and that its overall headcount could grow.

At rival investment bank Goldman Sachs, CEO David Solomon on Tuesday issued his own vision statement around how the company would reorganize itself around AI. Goldman is coming off a quarter where profit surged 37% to $4.1 billion.

“To fully benefit from the promise of AI, we need greater speed and agility in all facets of our operations,” Solomon told employees in a memo this week.

“This doesn’t just mean re-tooling our platforms,” he said. “It means taking a front-to-back view of how we organize our people, make decisions, and think about productivity and efficiency.”

The upshot for his workers: Goldman would “constrain headcount growth” and lay off a limited number of employees this year, Solomon said.

Goldman’s AI project will take years to implement and will be measured against goals including improving client experiences, higher profitability and productivity, and enriching employee experiences, according to the memo.

Even with these plans, which is first looking at reengineering processes like client onboarding and sales, Goldman’s overall headcount is rising this year, according to bank spokeswoman Jennifer Zuccarelli.

The comments around AI from the largest U.S. banks mirror those from tech giants including Amazon and Microsoft, whose leaders have told their workforces to brace for AI-related disruptions, including hiring freezes and layoffs.

Companies across sectors have become more blunt this year about the possible impacts of AI on employees as the technology’s underlying models becomes more capable and as investors reward businesses seen as ahead on AI.

In banking, the dominant thinking is that workers in operational roles, sometimes referred to as the back and middle office, are generally most exposed to job disruption from AI.

For instance, in May a JPMorgan executive told investors that operations and support staff would fall by at least 10% over the next five years, even while business volumes grew, thanks to AI.

At Goldman Sachs, Solomon seemed to warn the firm’s 48,300 employees that the next few years might be uncomfortable for some.

“We don’t take these decisions lightly, but this process is part of the long-term dynamism our shareholders, clients, and people expect of Goldman Sachs,” he said in the memo. “The firm has always been successful by not just adapting to change, but anticipating and embracing it.”