Federal law does not tax a billion dollars all at once. Taxes on a billion dollars come due in pieces: up to 37% on wages and other ordinary income, up to 23.8% on long-term investment gains when assets are sold, and 40% on the portion of an estate above a $15 million exemption when wealth passes at death. What actually gets collected depends on whether the fortune is earned, held, borrowed against, given away, or inherited.
Why a Billion in Wealth Isn’t a Billion in Taxable Income
The federal income tax reaches realized income, not net worth. Owning a billion dollars in stock, real estate, or private business equity creates no federal income tax bill by itself. If a company’s share price doubles overnight, the shareholder owes nothing until shares are sold or a taxable distribution arrives.
Taxable income is what is actually received during the year: wages, interest, dividends, or profit from selling an asset. That is why billionaires often report annual taxable income that looks small next to their net worth. Someone holding $5 billion in appreciated stock who sells none of it has zero taxable income from that stock. The gap between wealth and taxable income is not a loophole. It is the design of the income tax. The consequences of that design, especially around borrowing and inheritance, are where the real answer lives.
What Ordinary Income Would Be Taxed
Ordinary income covers wages, salaries, short-term trading profits, and most active business income. It runs through progressive brackets, so no one pays the top rate on every dollar. For 2026, the top marginal rate is 37%, applying only to taxable income above $640,600 for single filers or $768,700 for married couples filing jointly.1Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026 Income below those thresholds is taxed at rates from 10% to 35%.2Internal Revenue Service. Federal Income Tax Rates and Brackets
Few billionaires draw large salaries. The 37% bracket mostly hits executives with significant cash compensation or business owners whose profits flow through to a personal return. For fortunes built on appreciated assets, the interesting rates sit elsewhere.
What Selling Assets Would Cost
When an asset held more than a year is sold, the profit is a long-term capital gain. Federal law taxes long-term gains at lower rates than ordinary income. This is the single most important feature of the code for anyone whose wealth is tied up in appreciated holdings.
The top statutory rate on long-term capital gains is 20%, applying in 2026 to taxable income above $545,500 for single filers and $613,700 for joint filers.3Internal Revenue Service. Topic No. 409, Capital Gains and Losses Qualified dividends get the same preferential rates. For someone realizing gains in the hundreds of millions, effectively the whole gain lands in the 20% bracket.
Two surtaxes push the effective federal rate higher. The Net Investment Income Tax adds 3.8% on investment income for taxpayers whose modified adjusted gross income exceeds $200,000 (single) or $250,000 (married filing jointly).4Office of the Law Revision Counsel. 26 USC 1411 – Imposition of Tax For any billion-dollar portfolio, that threshold is irrelevant and the NIIT applies to essentially all investment income. Combined, the base rate and the NIIT bring the maximum federal rate on realized long-term gains to 23.8%.
One statutory carve-out matters at this level. Under Section 1202 of the Internal Revenue Code, gains from selling qualified small business stock held at least five years can be excluded from federal income tax up to the greater of $15 million or ten times the original investment. The stock must have been issued by a domestic C corporation with assets under $50 million at the time of issuance, and the qualifying rules are strict. For founders who meet them, early-stage investing becomes one of the most tax-efficient routes to a fortune in the entire code.
The rest of what a billion dollars pays in tax, however, turns less on the rates above than on whether assets are sold at all.
Borrowing Against Wealth Instead of Selling
A cash need can be met two ways. Sell appreciated stock and pay up to 23.8% on the gain, or borrow against the stock and pay no income tax at all.
Loan proceeds are not taxable income. A loan creates an obligation to repay, so there is no net gain in wealth. Securities-backed lines of credit let borrowers pledge investment portfolios as collateral and draw cash without selling a share.5FINRA. Securities-Backed Lines of Credit Explained Interest is owed, but historically at rates well below the tax cost of selling.
Tax researchers call the resulting pattern “buy, borrow, die.” Buy assets that appreciate, borrow against them to fund spending, hold them until death. At that point, as the next section explains, the accumulated gain disappears for income tax purposes. The loan is repaid from the estate, and the heirs receive assets with a clean slate. A lifetime of appreciation can escape the capital gains tax entirely.
The Step-Up in Basis at Death
Assets passed to heirs receive a new tax basis equal to their fair market value on the date of death.6Office of the Law Revision Counsel. 26 US Code 1014 – Basis of Property Acquired From a Decedent This is the step-up in basis, and it is the most consequential income tax provision for dynastic wealth.
Picture a founder who bought stock for $1 million that grew to $500 million over 30 years. Sold during life, that sale produces $499 million of taxable gain. Held until death, the heir’s basis resets to $500 million.7Internal Revenue Service. Gifts and Inheritances If the heir sells immediately for $500 million, the taxable gain is zero. Nearly half a billion in appreciation moves without ever facing the income tax.
The estate may still owe federal estate tax on the value of those assets, but the capital gains liability is gone for good. On a fortune built from appreciated holdings, this single provision can wipe out hundreds of millions in potential income tax in a single generational transfer.
Federal Estate and Gift Tax on a Billion-Dollar Estate
The federal government taxes large transfers of wealth, whether during life through the gift tax or at death through the estate tax. The two operate as a unified system with a shared exemption and a top rate of 40%.8Office of the Law Revision Counsel. 26 US Code 2001 – Imposition and Rate of Tax
For 2026, each individual can transfer up to $15 million during life or at death without triggering federal transfer tax.9Internal Revenue Service. Whats New – Estate and Gift Tax A married couple can shelter up to $30 million combined. Anything above the exemption is taxed at 40%. On a billion-dollar estate, roughly $985 million would sit above a single exemption, producing a potential federal estate tax bill approaching $394 million. Transfers to a U.S.-citizen spouse are unlimited and tax-free under the marital deduction.
Wealthy families reduce that exposure with irrevocable trusts, including grantor retained annuity trusts. The idea is to move assets into a trust structured so that the initial gift has little or no taxable value, while future appreciation grows outside the taxable estate. These techniques are legal but complex, and they account for much of the difference between what a billion-dollar estate could owe on paper and what one actually pays.
A separate rule targets attempts to leapfrog a generation. The generation-skipping transfer tax adds a flat 40% on transfers that skip a generation, whether outright, by bequest, or through a trust. Its 2026 exemption also sits at $15 million per person.9Internal Revenue Service. Whats New – Estate and Gift Tax Transfers above the exemption can be hit with both the estate tax and the generation-skipping tax, making unplanned transfers to grandchildren extremely expensive.
Charitable Giving Reshapes the Bill
Charitable contributions cut tax in two ways at once. Donating appreciated assets directly to a qualified charity or donor-advised fund avoids capital gains tax on the donated assets, and the donor deducts the full fair market value against income. For cash donations, the deduction can offset up to 60% of adjusted gross income in a given year. For donated appreciated property, the limit is 30% of AGI. Unused deductions carry forward up to five years.
Private foundations let a donor claim an upfront deduction while retaining long-term control over charitable spending. Federal law requires a private foundation to distribute at least 5% of its net investment assets each year for charitable purposes.10Office of the Law Revision Counsel. 26 USC 4942 – Taxes on Failure to Distribute Income A foundation that misses the minimum faces an initial 30% penalty tax on the undistributed amount and a 100% penalty if the shortfall is not corrected within the allowed period. The 5% floor stops indefinite warehousing, but 95% of the assets can remain invested and growing tax-free year after year.
Donor-advised funds work more simply. The donor contributes, takes an immediate deduction, and later recommends grants. Federal law imposes no minimum annual distribution on donor-advised funds. That has drawn criticism, and it is still the rule.
State Taxes and Foreign Accounts
Everything above is federal. A dozen states and the District of Columbia impose their own estate taxes, some with exemptions starting below $2 million. A handful of states also impose inheritance taxes, paid by the recipient rather than the estate. State income tax rates on high earners run from zero to over 13% and stack on top of federal rates. Domicile at death and the location of real property can add tens of millions in tax that federal planning alone will not address.
Offshore holdings bring their own layer, though of reporting rather than a separate income tax. Any U.S. person with foreign financial accounts whose combined value exceeds $10,000 at any point during the year must file a Report of Foreign Bank and Financial Accounts with FinCEN, and willful violations can trigger penalties equal to the greater of $100,000 or 50% of the account balance.11Internal Revenue Service. Report of Foreign Bank and Financial Accounts (FBAR) A separate FATCA requirement adds Form 8938 for specified foreign financial assets above modest thresholds.12Internal Revenue Service. Do I Need to File Form 8938, Statement of Specified Foreign Financial Assets Any billionaire with offshore accounts will clear both. These rules govern disclosure, not the rates that determine what a billion dollars actually pays.