Can California Tax You After You Leave?The Billionaire Wealth Tax Fight Just Went Federal

What happens if a state tries to tax you — even after you’ve moved away?

That’s the question now driving a growing legal and political showdown over California’s proposed 2026 Billionaire Tax Act, a ballot initiative that would impose a one-time 5% tax on the worldwide net worth of billionaires who were California residents as of January 1, 2026.

Supporters argue it could raise massive revenue for healthcare and social programs. Critics warn it could trigger high-profile relocations, and potentially attempt to tax individuals who no longer live in the state.

Now, a federal bill aims to stop that from happening.

What the Proposed 2026 Billionaire Tax Would Do

Backers of the initiative are working to place the measure on California’s November 2026 ballot. If approved, it would:

• Impose a one-time 5% excise tax
  
  
• Apply to individuals or trusts with net worth of $1 billion or more
  
  
• Use January 1, 2026 residency status as the benchmark date
  
  
• Apply to worldwide assets

Revenue would primarily fund healthcare programs, with remaining funds allocated to education and food assistance.

According to information from the California Legislative Analyst’s Office (LAO), the tax could generate “tens of billions of dollars” over several years beginning in 2027. However, the LAO also warned the proposal could cause an ongoing reduction in state income tax revenue, potentially hundreds of millions annually, if affected individuals relocate.

The Federal Pushback: The Keep Jobs in California Act

In response, U.S. Representative Kevin Kiley (R-CA) introduced the federal bill, Keep Jobs in California Act (H.B. 7619).

The bill would prohibit any state from imposing a retroactive tax on a nonresident individual’s assets for any period before the tax was enacted if that individual no longer resides in the state.

In practical terms, Kiley described the proposed wealth tax as an “unprecedented attempt” to impose retroactive taxation on individuals who have already left the state.

Importantly, the federal bill does not prohibit states from taxing current residents. It focuses specifically on retroactive or post-departure asset taxation.

Why Retroactive Wealth Taxes Raise Legal Questions

Retroactive taxation is not new, but wealth taxes present distinct constitutional questions. Legal analysts have pointed to potential concerns involving:

• Due Process protections
  
  
• The constitutional right to travel
  
  
• Commerce Clause limitations
  
  
• The scope of state authority to tax worldwide assets

California already uses a complex residency test based on domicile, time spent in the state, and intent. Any attempt to tax former residents would likely face immediate legal challenges.

The Migration Risk

Thanks to the presence of industries like technology and entertainment, California relies heavily on high-income earners for a significant share of its revenue. The LAO analysis explicitly acknowledged that behavioral changes — including relocation — could reduce long-term income tax collections by hundreds of millions of dollars annually.

That tension is central to the debate: short-term revenue gains versus potential long-term tax base erosion.

Competing Ballot Measures Add Complexity

Multiple additional initiatives have been filed that could complicate or counteract the 2026 Billionaire Tax Act if they qualify for the ballot. These include proposals that would:

• Raise the voter threshold to two-thirds for new one-time taxes
  
  
• Prohibit new taxes on personal savings and retirement assets
  
  
• Clarify residency rules for nonresidents and part-time residents
  
  
• Increase fiscal transparency measures

The proposed California billionaire wealth tax, and the federal Keep Jobs in California Act designed to counter it, represent a direct confrontation between state revenue authority and constitutional limits.

If the ballot initiative advances and the federal bill gains traction, this could become one of the most closely watched state tax disputes in recent history.

For taxpayers, the takeaway is straightforward: Residency is not just a mailing address. It can determine whether your wealth is taxable, even after you move.