What Percentage of Billionaires’ Wealth Growth Actually Gets Taxed?

United States – February, 20, 2026

When people say billionaires “already pay plenty in taxes,” they are usually talking about taxable income.

But that leaves out the more important question:

What percentage of their total economic gain actually gets taxed?

That distinction changes the entire conversation.

This isn’t about slogans. It’s about mechanics.

Income Is Not the Same as Wealth Growth

Most ultra-wealthy Americans do not primarily earn wages.

Their wealth grows through:

Stock appreciation
Ownership stakes in private companies
Real estate appreciation
Venture capital investments
Capital gains

If a billionaire’s net worth rises by $10 billion in a year and they don’t sell anything, that increase is:

Unrealized gain — and it is not taxed under current U.S. law.

That’s not a loophole in the shadows. It’s how the tax system is designed.

Taxes apply when gains are realized — meaning when assets are sold.

As long as assets are held, the gain exists economically but not taxably.

The “Buy, Borrow, Die” Strategy

This structure allows a powerful wealth strategy often summarized as:

Buy, Borrow, Die.

Here’s how it works:

Buy assets (stock, equity, real estate).
Let them appreciate.
Borrow against them instead of selling.
At death, pass them to heirs with a step-up in basis.

Borrowing is not taxable income.

Because assets aren’t sold, capital gains tax is not triggered.

At death, the step-up in basis resets the asset’s taxable value to current market value, meaning decades of appreciation can permanently avoid capital gains tax.

This provision is built into U.S. tax law.

It is legal.

But it dramatically changes how effective tax rates look when measured against total wealth growth.

How Effective Tax Rates Look Under Different Measures

Traditional tax statistics measure taxes as a percentage of reported taxable income.

Under that measurement:

High-income households pay large dollar amounts.
Federal income taxes are progressive.
Top earners face higher marginal rates.

But if you measure taxes as a percentage of true economic gain, including unrealized appreciation, the picture changes.

An analysis by ProPublica using IRS data from 2014–2018 estimated that some billionaires paid extremely low effective rates when comparing total taxes paid to total wealth growth during that period.

That analysis was debated, because unrealized gains are not considered income under the tax code.

But economically, unrealized gains increase financial power, borrowing capacity, and long-term wealth concentration.

That’s where the fairness question begins.

Why This Debate Matters

Middle-income households:

Pay taxes annually on nearly all their earnings.
Cannot indefinitely defer taxation.
Cannot borrow billions against appreciated stock.
Do not receive large-scale step-ups in basis.

Their effective tax rates are calculated on almost all of their economic gain.

For ultra-wealthy households, large portions of annual wealth growth may never face taxation at all.

That difference — not the marginal rate on taxable income — is what drives the frustration many Americans feel.

Public Investment and Private Fortunes

Modern wealth creation has also been intertwined with public investment.

Technologies foundational to today’s largest fortunes trace back to publicly funded research, including:

Internet infrastructure (DARPA research)
GPS (Department of Defense programs)
Space and aerospace technologies developed through NASA – National Aeronautics and Space Administration
Biomedical innovation funded by the National Institutes of Health

Private entrepreneurship transformed these breakthroughs into companies and industries.

But public funding laid much of the groundwork.

That raises a reasonable question:

If public investment helps generate massive private wealth, how should the resulting gains contribute back to the system?

Where the Real Policy Debate Lives

The meaningful policy questions are structural:

Should unrealized gains for ultra-high-net-worth individuals be taxed annually?
Should the step-up in basis at death be eliminated or limited?
Should borrowing against appreciated assets trigger partial tax recognition?

Each proposal would significantly alter how concentrated wealth is taxed.

Each also raises practical challenges:

Liquidity issues
Asset valuation disputes
Market volatility concerns
Constitutional questions

This is not a simple argument about success versus fairness.

It’s a debate about how labor income and capital appreciation are treated differently in the tax system.

Billionaires do pay taxes.

But the key question is:

Do they pay taxes proportional to their total economic gain?

Under current law:

Labor income is taxed annually.
Capital gains are taxed when realized.
Unrealized gains are not taxed.
Step-up in basis can erase decades of deferred capital gains.

If we want an informed discussion about tax fairness in America, we have to start with clarity about what is taxed — and what is not.

The conversation isn’t about whether wealthy Americans pay something.

It’s about whether the structure of the system aligns with our shared definition of fairness.