Silicon Valley, the innovation hub of the world and home to some of the most successful tech companies, could soon turn into a ghost town — at least that’s the dire warning from billionaire hedge fund manager Bill Ackman.

 “It would be catastrophic to California,” Ackman told The Post. “Every successful founder, entrepreneur would leave. Literally no one would stay.”

Already, the ultra-rich are making plans to flee the Golden State over a proposed one-time 5% wealth tax on residents worth more than $1 billion, multiple sources confirmed to The Post last week.

Supporters argue the 2026 Billionaire Tax Act will raise up to $100 billion in revenue over five years, and would go toward replenishing health care, education and nutrition funds that were lost to federal funding cuts.

Suzanne Jimenez, a chief of staff for SEIU-United Healthcare Workers West labor union — the main force behind the tax measure — called the billionaire tax “literally a dollar-for-dollar solution” to federal cuts to the health care system, adding that the one-time 5% wealth tax is a “very minor tax.”

But even California Gov. Gavin Newsom is reportedly against the proposal that would impact roughly 200 people.

Chris Edwards, an economist at the Cato Institute, said imposing a wealth tax would result in less business in California and would hurt the economy.

“The top tier of individuals, the Steve Jobs, Jeff Bezos, Elon Musk, yes their paper asserts are big — $50 billion, $100 billion — 95% of that is business assets, that’s what they own. So, their ownership of those businesses benefits all of us. Bezos’ company employs a million Americans,” Edwards told The Post. “So, imposing a tax on wealth is imposing a tax on business assets in California, the result will be less business assets in California.”

Ackman, the CEO of Pershing Square Holdings, acknowledged that billionaires are getting away without paying their fair share in taxes, largely by “living off loans secured by stock in the company.”

“Effectively you can live an extraordinarily, you know, lavish life, and not pay tax if you just borrow against appreciated stock and that just doesn’t sound fair,” he told The Post.

While Ackman doesn’t support a wealth tax, he proposed on X that the “personal loans taken in excess of one’s basis in the stock of a company should be taxable as if you sold the same dollar amount of stock as the loan amount.”

“In a sense, you borrow against your stock, you’re getting liquidity that you can use to live your life, right? It’s tantamount to having sold your shares,” Ackman said.

Edwards said California really should look at raising the sales tax if it wants a long-term solution.

“I think the solution rather than Ackman’s idea of imposing something new, would be relying more heavily on sales taxes, because they hit everyone,” Edwards said. “If wealthy people go out and buy yachts and the like, then they’re gonna be hit by heavy sales taxes.”

The statewide sales tax base rate is 7.25% in California, which can go as high as 10.75%, depending on what local and district taxes are added on.

The measure needs to garner around 870,000 signatures by next spring to qualify for the ballot.