A person worth a billion dollars can legally owe very little federal income tax in any given year, because the federal government taxes income that is actually received, not wealth that sits on paper. When wealth does get taxed, the main rates are 23.8% on long-term investment gains and 40% on the portion of an estate above $15 million. The practical answer to how much tax a billion dollars attracts depends almost entirely on whether the owner sells assets during life, borrows against them, gives them away, or holds them until death.
Why a Billion in Net Worth Isn’t Taxed on Its Own
Federal income tax applies to realized income: wages, interest, dividends, and profit from selling an asset. Holding $1 billion in stock, real estate, or private business equity does not create a tax bill by itself. If the shares double in value overnight, the owner owes nothing until they sell or receive a taxable distribution.
This is why billionaires routinely report annual taxable income that looks small next to their net worth. Someone sitting on $5 billion in appreciated stock who sells none of it has zero taxable income from that stock. The gap between wealth and taxable income isn’t a loophole; it’s the structure of the income tax. But the rest of the code — borrowing rules, the basis step-up, and the estate tax — turns that structure into a serious advantage for anyone with enough assets to avoid selling.
What a Billionaire Pays When They Actually Sell
When a billionaire sells an asset held more than a year, the profit is a long-term capital gain. The top statutory rate is 20%, which for 2026 applies to taxable income above $545,500 for single filers and $613,700 for joint filers.1Internal Revenue Service. Topic No. 409, Capital Gains and Losses Qualified dividends get the same preferential treatment. For a gain measured in hundreds of millions, nearly all of it lands in the 20% bracket.
Two additional federal taxes stack on top. The Net Investment Income Tax adds 3.8% on investment income — gains, dividends, interest, rent — once modified adjusted gross income passes $200,000 single or $250,000 joint.2Office of the Law Revision Counsel. 26 USC 1411 – Imposition of Tax At the billion-dollar level, that threshold is irrelevant and the 3.8% applies to essentially all investment income. The Additional Medicare Tax adds another 0.9% on wages and self-employment income above the same thresholds, which hits only earned income.3Internal Revenue Service. Questions and Answers for the Additional Medicare Tax
Combine the 20% capital gains rate with the 3.8% surtax and the maximum federal rate on long-term gains is 23.8%. That’s the ceiling on what a sale actually costs — and it’s well below the 37% top rate on ordinary wages, which is why the distinction between selling stock and drawing a salary matters so much at this level of wealth.
Borrowing Instead of Selling
Here the tax picture diverges sharply from what most people experience. If cash is needed and the wealth sits in appreciated stock, there are two choices: sell and pay up to 23.8% in federal tax on the gain, or borrow against the stock and owe nothing in income tax.
Loan proceeds are not taxable income. A loan creates an obligation to repay, so there’s no net increase in wealth. Securities-backed lines of credit let the borrower pledge an investment portfolio as collateral and draw cash without selling a share.4FINRA. Securities-Backed Lines of Credit Explained Interest costs money, but historically far less than the tax cost of a sale.
This is the pattern tax researchers call “buy, borrow, die.” Buy assets that appreciate, borrow against them to fund spending, hold until death. The loan is repaid from the estate, and — as the next section explains — the accumulated gains disappear for income tax purposes. A lifetime of appreciation can escape the capital gains tax entirely.
The Step-Up in Basis at Death
Assets passed to heirs get a new tax basis equal to their fair market value on the date of death.5Office of the Law Revision Counsel. 26 US Code 1014 – Basis of Property Acquired From a Decedent This is the step-up in basis, and for dynastic wealth it is arguably the most consequential provision in the code.
Consider a founder who bought stock for $1 million that grew to $500 million over 30 years. Selling during life would mean capital gains tax on $499 million of profit. Holding until death resets the heir’s basis to $500 million.6Internal Revenue Service. Gifts and Inheritances If the heir then sells for $500 million, the taxable gain is zero. Nearly half a billion dollars in appreciation passes without being touched by the income tax.
The estate may still owe federal estate tax on the value of those assets, but the capital gains liability vanishes permanently. On a fortune built from appreciated holdings, this provision can eliminate hundreds of millions in potential income tax in a single transfer.
Federal Estate, Gift, and Generation-Skipping Tax
The federal transfer tax is where a billion-dollar fortune actually meets a serious bill. Lifetime gifts and bequests at death are taxed under a unified system with a shared exemption and a top rate of 40%.7Office 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 any federal transfer tax.8Internal Revenue Service. Whats New – Estate and Gift Tax A married couple can shelter $30 million combined. Everything above gets taxed at 40%. On a $1 billion estate, roughly $985 million falls above the exemption, producing a potential federal estate tax bill near $394 million.
Each person can also give up to $19,000 per recipient per year without using any lifetime exemption, and gifts to a U.S. citizen spouse are unlimited under the marital deduction.8Internal Revenue Service. Whats New – Estate and Gift Tax Wealthy families use the annual exclusion systematically across many recipients and years, and they use irrevocable trust structures — such as grantor retained annuity trusts — to shift future appreciation out of the taxable estate. The idea is to transfer assets in a form where the initial gift has little taxable value, letting the growth land with beneficiaries free of further estate and gift tax. These strategies are legal, complex, and account for much of the gap between what a billion-dollar estate could owe in theory and what it actually pays.
The generation-skipping transfer tax closes an obvious workaround. Without it, a billionaire could leave wealth directly to grandchildren and skip the estate tax on an entire generation. The GST applies a flat 40% to transfers that skip a generation, with a 2026 exemption matching the estate tax exemption at $15 million per person.8Internal Revenue Service. Whats New – Estate and Gift Tax Amounts over that cap can face both the estate tax and the GST, making the combined effective rate on unplanned generational transfers steep.
Charitable Giving
Charitable giving is the main legal lever for reducing both income tax and estate tax on a billion-dollar fortune. Donating appreciated assets directly to a qualified charity or donor-advised fund avoids capital gains tax on those assets, and the donor claims an income tax deduction for the full fair market value. Cash donations can offset up to 60% of adjusted gross income in a given year; donated appreciated property is capped at 30% of AGI. Unused deductions carry forward for up to five years.
Private foundations let a donor take an upfront deduction while keeping long-term control of charitable spending. Federal law requires foundations to distribute at least 5% of net investment assets each year toward charitable purposes.9Office of the Law Revision Counsel. 26 USC 4942 – Taxes on Failure to Distribute Income A foundation that misses the floor faces a 30% penalty tax on the undistributed amount, rising to 100% if it isn’t corrected in time. The 5% rule stops indefinite warehousing, but the other 95% can keep compounding tax-free.
Donor-advised funds are the simpler route: contribute assets, take an immediate deduction, recommend grants over time. There is no minimum annual distribution requirement for donor-advised funds under current federal law.
State Taxes Add Another Layer
Everything above is federal only. A dozen states and the District of Columbia impose their own estate taxes, with exemptions that can run dramatically lower than the federal threshold, some starting below $2 million. A handful of states impose inheritance taxes paid by the recipient. State income tax rates on high earners range from zero in no-tax states to over 13% in the highest-tax states, stacked on top of federal rates.
For a billion-dollar fortune, state of residence at death and the location of real property can add tens of millions in liability beyond what the federal government collects. That is why domicile and asset location get as much planning attention as anything in the federal code.
Foreign Account Reporting Sits on Top of the Tax
Any U.S. person with foreign financial accounts whose combined value exceeds $10,000 at any point in the year must file a Report of Foreign Bank and Financial Accounts (FBAR) with the Financial Crimes Enforcement Network.10Internal Revenue Service. Report of Foreign Bank and Financial Accounts (FBAR) Willful violations can draw penalties equal to the greater of $100,000 or 50% of the account balance.
A separate rule under the Foreign Account Tax Compliance Act requires reporting specified foreign financial assets on Form 8938 if their total value exceeds $50,000 on the last day of the tax year or $75,000 at any point during the year for single filers; joint filers have higher thresholds of $100,000 and $150,000.11Internal Revenue Service. Do I Need to File Form 8938, Statement of Specified Foreign Financial Assets Both thresholds are low enough that any billionaire with offshore holdings triggers them, and the penalties for noncompliance are large enough that this is one area where mistakes cost more than the tax itself.