Google co-founder Sergey Brin — who has been leading the campaign against California’s billionaire’s tax — has turned his vast fortune to to San Francisco politics.

Brin has already shifted himself from Silicon Valley’s liberal bubble for a sprawling Nevada hideaway perched on the edge of Lake Tahoe, just beyond the reach of the tax.

But that hasn’t stopped the billionaire, who’s worth a staggering $260 billion, from dropping $500,000 into a committee opposing the city’s so-called “Overpaid CEO Tax”, while supporting a competing, more business-friendly tax measure.

San Francisco voters are set to weigh in on Measures C and D, two competing proposals on the June 2 ballot that would radically reshape the city’s business tax system.

The first, backed by business groups, would expand tax exemptions for smaller businesses in San Francisco — raising the cutoff from $5 million to $7.5 million in revenue — while accelerating scheduled tax increases on larger companies, particularly through higher executive pay tax rates starting in 2027.

Measure D, the so-called Overpaid CEO Act, would broaden a tax on CEOs by basing the figure on a company’s entire workforce, not just San Francisco employees.

It would also significantly raise tax rates and lock them in place by requiring voter approval to reduce it.

Labor unions and far-left progressives support Measure D, “to make sure the wealthiest corporations pay their fair share,” said the Chinese Progressive Association.

But business interests oppose the act, saying it “doubles down on the exact policies that are driving jobs out and driving vacancies up,” said Steven Buss, co-director of the political advocacy group GrowSF.

A May 14 analysis by San Francisco’s Office of the Controller estimated that Measure D would lead to the loss of 944 jobs and $210 million worth of GDP over the next two decades.

Meanwhile, Measure C will have only a small benefit, the office said, with a net gain of 90 jobs and $20 million GDP growth in the same time.

Brin’s financial backing is notable and also in line with his antagonism toward wealth taxes that have spurred his political activism this year.

Brin has put tens of millions of his own money into fighting a proposed one-time billionaire tax that would affect the entire state.

He has reportedly fled to Nevada to escape the potential wealth tax that may go before California voters in November.

Some of the political changes have been attributed to Sergey Brin’s “MAGA girlfriend” Gerelyn “GG” Gilbert-Soto, but she pushed back on claims that she dragged the Google co-founder to the political right, insisting the billionaire tech mogul’s political change of heart can be laid squarely at the feet of Democrats.

As for why he feels so strongly about wealth taxes, Brin issued a rare statement in April: “I fled socialism with my family in 1979 and know the devastating, oppressive society it created in the Soviet Union.

”I don’t want California to end up in the same place.”