The head of an influential Big Apple business advocacy group warned that companies are already taking steps to relocate or move jobs elsewhere because of Mayor Zohran Mamdani’s tax-hike crusade.

Steve Fulop, CEO of the Partnership for the City of New York, said many corporations are considering leaving or shifting their workforces to less costly states after it was revealed $900 billion asset manager Apollo Global Management is plotting a second US headquarters in the Sunbelt.

“In the last week, there have been several [major companies] in the Partnership that have said they’re going down the same road [as Apollo], exploring options in Florida and Texas,” Fulop said Sunday on 77 WABC Radio’s “Cats Roundtable.”

“Some of these [firms] … are major New York City brands that have been headquartered here for 100 years. The fact is – they’re leaving,” Fulop told host John Catsimatidis.

Fulop later declined to name the firms seriously weighing abandoning or de-emphasizing jobs in the Big Apple when contacted by The Post.

“I’m not going to get into specific names or speculate on who is down the road of leaving,” Fulop said. “It’s not appropriate to front-run a company announcement, especially when many of these firms have large employee bases in New York.

“What I can say clearly and unequivocally is that Apollo’s move is not an isolated case,” he went on. “It reflects a broader trend tied directly to competitiveness and business leaders feel that some elected officials are tone deaf to the broader economic environment and have no realistic long term plan to fix the affordability crisis beyond raising costs which will only further the challenges.”

He noted that JP Morgan boss Jamie Dimon last week said New York State’s high-tax climate puts it at a competitive disadvantage.

The Partnership this week is bankrolling a multi-million dollar ad campaign to encourage Gov. Kathy Hochul (D) to stare down Mamdani and hold the line on taxes.

Mamdani, a democratic socialist who became mayor in January after campaigning on a freebie-filled progressive agenda, has floated a menu of tax hikes to generate money for the city that includes increasing income taxes on the wealthy, boosting the estate tax and upping the corporate tax.

All of those options would need approval from the state, but Hochul — who is up for re-election this year — has resisted the push despite mounting pressure from the leftwing of his party.

Mamdani has continued to beat the drum that tax hikes are needed and he even threatened to hike local property taxes 9.5% if the state doesn’t OK his other proposals. He has said the extra income is needed to close a projected $5.4 billion in the city budget due July 1.

But his message was undercut by the City Council, which released a financial analysis last week claiming the city’s massive $127 billion budget could be balanced without tax hikes.

Fulop said his group wants to make sure new taxes “are going to force people out of here.”

“You need to be able to communicate broadly how fragile the economy is and that some of these legislators who are pushing tax increases for the sake of tax increases are really not thinking about the long-term best interests of the city and region,” Fulop said.

He said the support for the ad campaign comes from a portion of annual dues paid by the Partnership’s 300 members, not just members of the group’s executive board.

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The state budget was due April 1, but Hochul and the Democratic-run legislature are still in talks over whether to hike taxes.

During last year’s mayoral campaign, Mamdani proposed raising the top corporate income tax rate for major corporations from 7.25% to 11.5%.

Another Mamdani proposal would increase the city’s corporate tax from 9% to 10.8% on financial sector firms and 8.85% to 10.62% on non-finance sectors. His team projected that such an increase would raise $1.5 billion a year.

The Democrat-run state Assembly and Senate are considering their own corporate tax proposals similar to Mamdani’s.

The Assembly estimates that its own proposal to increase the statewide corporate tax from 7.25% to 9.25% for companies making more than $10 million would generate around $1.9 billion per year in revenue.

The Senate proposes increasing the statewide corporate tax rate from 7.25% to 9% for businesses with $5 million in income.

Mamdani’s office rebutted Fulop’s claim of a corporate exodus as scare mongering.  

“The most recent jobs data indicate that New York City added more than 10,000 private sector jobs in January and is now on the path to surpassing the all-time high for total jobs in the city. The labor force participation rate is at its highest point in history. Manhattan’s office space market just reached its highest point in more than a decade,” a Mamdani spokesperson said..  

“The fact is that corporations continue to invest and expand in New York City because of our unmatched talent pool and world-class amenities. The data shows that working people, on the other hand, have been continuously pushed out of the city in recent decades by the affordability crisis. Mayor Mamdani is focused on continuing to grow the city’s economy, while ensuring that all New Yorkers benefit from that growth – not just the select few,” added the City Hall rep.

 The mayor’s office noted that Bank of America recently signed a 20-year at One Bryant Park and  American Express announced plans for a new global headquarters in lower Manhattan.