California has a lot of billionaires, more than any other state and more than most countries. So a proposed wealth tax on its billionaires could be a windfall, if they stick around.

Under the Billionaire Tax Act, California residents worth over $1 billion would face a one-time tax totaling 5% of their assets.

If the tax plan receives enough signatures, it will appear on the ballot in November and, if passed, would apply retroactively to billionaires living in the state as of January 1. The tax would be due in 2027, with the option to spread the payment out over five years, with interest.

The idea has drawn sharp reactions from lawmakers and business leaders.

Google cofounders Larry Page and Sergey Brin moved entities tied to them out of the state last month just ahead of the deadline, Business Insider first reported.

Nvidia CEO and billionaire Jensen Huang said he was "perfectly fine" with the tax. Palmer Luckey, the billionaire founder of defense tech startup Anduril, said it would force companies to "immediately pivot into profit obsession over mission or long-term sustainability."

Critics of the tax have warned it will encourage ultrawealthy residents to flee the state and hurt California's economy.

As of January 1, there were 214 billionaires in California, according to Forbes data compiled by Americans for Tax Fairness, a group that advocates for higher taxes.

Below is the full list of billionaires in California. Names with asterisks have recently moved at least some of their business entities out of the state.