CBO Scores OBBBA's Tax Cuts at $3.4 Trillion Added to Deficits

The Congressional Budget Office reported on July 21, 2025 that the One Big Beautiful Bill Act, signed into law on July 4 as Public Law 119-21, will add $3.4 trillion to federal deficits from 2025 through 2034, measured against CBO's January 2025 baseline. Including the extra interest cost of financing that larger debt, CBO put the total effect at $4.1 trillion over the decade. The estimate, published as CBO publication 61570, is the official nonpartisan scorekeeper's final word on the law's fiscal footprint, and it lands squarely on the question of how long today's lower rates and larger exemptions can last.

What the score actually says

CBO's $3.4 trillion figure reflects the net of two large moving pieces: an extension and expansion of the 2017 individual tax cuts, along with new provisions such as increased estate and gift tax exemptions and business expensing, that reduce projected revenue, partly offset by spending reductions elsewhere in the law, notably in Medicaid and nutrition programs. A companion CBO estimate found that making certain of the law's tax provisions permanent, rather than assuming they expire on schedule under current law, would add further tens of billions in interest costs on top of the base score. The bill passed without Democratic votes, and CBO's projections do not depend on which party controls future Congresses.

Why this matters for high earners

Households with income well above the median tend to benefit disproportionately from the law's permanent individual rate structure, the expanded standard deduction, and the estate tax exemption, now scheduled to stay near $15 million per person rather than reverting to roughly half that level. Because those provisions are law rather than expiring in a future year, families do not face the same use-it-or-lose-it planning deadline that drove estate planning ahead of the original 2025 sunset. But CBO's deficit math is also a signal about durability: a law that adds $3.4 trillion to projected deficits, on top of debt already near record levels relative to the economy, raises the odds that a future Congress revisits the revenue side, whether through new surtaxes, limits on itemized deductions, or a lower estate exemption, especially if control of government changes hands.

The after-tax math on policy risk

Illustrative example: a married couple with $2 million in taxable income under the law's permanent 37% top bracket pays roughly the same marginal rate today as they would have paid temporarily under the expiring 2017 rules. The difference is certainty. Under the prior law, that couple faced a near-certain jump to a 39.6% top rate after 2025 absent new legislation. Under the enacted law, no scheduled increase exists, so any future rate change would require Congress to act affirmatively, a materially different planning posture than betting against an automatic sunset.

What to watch

CBO's baseline will be updated again as the agency publishes its next full budget and economic outlook, and the debt-to-GDP trajectory implied by this law will remain a talking point in future tax debates. For affluent households, the practical takeaway is not that today's rates and exemptions are at risk of near-term reversal, since they are now written into permanent law, but that the size of the deficit CBO has attached to them keeps the door open to future legislative changes aimed at high earners, particularly around the estate tax exemption, the treatment of pass-through business income, or new surtaxes on investment income. Families doing multi-decade estate and gifting plans may still want a strategy that works reasonably well even if a future Congress narrows today's provisions, rather than one that only works if nothing changes.

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