San Francisco voters appear to have rejected a significant tax increase on highly paid corporate executives that had been opposed by some of the most powerful people in the tech industry.

The measure, Proposition D, which supporters referred to as the “Overpaid C.E.O. Tax,” had been backed by labor unions, which said that the city needed more money to improve services for everyday San Franciscans.

Just over 46 percent had approved the measure, while 53.6 percent of voters had chosen “no,” figures showed after San Francisco updated its election returns on Monday afternoon.

Many had viewed the measure as a signal of how residents were feeling amid a tremendous infusion of capital from an A.I. boom that has reshaped the city. The conversation in San Francisco mirrored a larger one around a billionaires’ tax expected to qualify for California’s November ballot.

But the measure was opposed by Mayor Daniel Lurie, as well as several prominent tech leaders, who argued that it would push businesses out of San Francisco and slow the city’s post-pandemic economic recovery. Sergey Brin, co-founder of Google, and Tony Xu, the co-founder of DoorDash, each spent hundreds of thousands of dollars to defeat the initiative.

It was the latest sign that San Francisco, despite its liberal image, has taken a more centrist tack in recent years. In 2022, the city ousted its progressive district attorney and recalled three school board members after they focused heavily on social justice initiatives while campuses were closed during the pandemic. In 2024, voters elected Mr. Lurie, a moderate Democrat who pledged to focus on quality of life matters.

Proposition D would have expanded a tax originally approved by voters in 2020 that essentially penalized companies with a large wage gap between employees and executives.

The tax currently applies to businesses with more than 1,000 employees and $1 billion in annual revenue, and that have top executives who make more than 100 times the median pay of their San Francisco employees.

Proposition D instead would have compared executive salaries to the median pay of all the company’s employees — not just those in San Francisco, where salaries tend to be significantly higher. The new measure also would have increased the tax rates imposed.

A city analysis found that Proposition D would have increased annual city revenues by $250 million to $300 million, but that it likely would have resulted in a loss of about 940 jobs in the city.