The MIT endowment tax is a federal excise tax on the investment income generated by MIT’s endowment. It currently sits at 1.4%, but a law signed on July 4, 2025 raises the top rate to 8% for taxable years beginning after December 31, 2025. MIT’s $27.4 billion endowment, measured as of June 2025, places the university in the highest bracket of the new structure, and MIT’s leadership says the change will cost roughly 10% of the university’s annual central budget.1MIT. Major Tax Impact on MIT and Its Mission The tax reaches only investment returns. Tuition, donations, and research grants are untouched.
The New Tiered Rate Structure
The “One Big Beautiful Bill Act” (Pub. L. 119-21) replaced the flat 1.4% rate that had applied since the Tax Cuts and Jobs Act of 2017 with three tiers, keyed to how much endowment wealth an institution holds per student:2Office of the Law Revision Counsel. 26 USC 4968 – Excise Tax Based on Investment Income of Private Colleges and Universities
- 1.4% for institutions with a student adjusted endowment between $500,000 and $750,000 per student.
- 4% between $750,000 and $2,000,000 per student.
- 8% above $2,000,000 per student.
The “student adjusted endowment” is the fair market value of the institution’s non-exempt-purpose assets divided by its student count, measured by daily average full-time equivalent enrollment. Assets used directly for the educational mission, such as classroom buildings, laboratories, and dormitories, do not count toward the per-student figure.3Internal Revenue Service. Excise Tax on Net Investment Income of Private Colleges and Universities
MIT has roughly 12,000 students and a $27.4 billion endowment, putting its per-student figure well above $2 million.4MIT. MIT Releases Financials and Endowment Figures for 2025 There is no close call. MIT is a top-bracket institution.
The 2025 law also lifted the student-count threshold for being subject to the tax at all. An institution must now have at least 3,000 tuition-paying students (up from 500), with more than half in the United States, and still meet the $500,000 per-student asset floor. MIT clears every threshold comfortably.
When the 8% Rate Actually Hits MIT
The new rates apply to taxable years beginning after December 31, 2025. MIT’s fiscal year runs July 1 to June 30, so the fiscal year ending June 30, 2026, which began before the cutoff, remains under the old 1.4% rate. The first MIT fiscal year taxed at 8% begins July 1, 2026 and ends June 30, 2027.
Assuming endowment values and returns stay in a similar range, MIT’s endowment tax bill will roughly quintuple starting with that 2026-2027 fiscal year.
What Gets Taxed: Net Investment Income
The rate applies to net investment income, not to the endowment’s total value. Gross investment income includes interest, dividends, rents, royalties, and payments on securities loans, with capital gains from selling investment property added on top.5GovInfo. 26 CFR 53.4968-2 – Net Investment Income The 2025 amendments also pulled student loan interest received by the institution and certain federally subsidized royalty income into that gross figure.
From gross investment income, the institution subtracts ordinary and necessary expenses tied to producing or managing that income, including investment advisory fees, custodial charges, and portfolio administration costs. The remainder is what the excise rate multiplies against.
Some rough math shows the stakes. MIT’s endowment returned 14.8% in the fiscal year ending June 30, 2025.4MIT. MIT Releases Financials and Endowment Figures for 2025 Applied to $27.4 billion, that is around $4 billion in gross investment gains before deductions. Net investment income on a portfolio that size is large enough that the difference between a 1.4% and an 8% rate runs to hundreds of millions of dollars in a strong return year.
What the 8% Rate Means for MIT’s Budget
MIT’s leadership described the new 8% rate as costing “in the range of 10% of our annual central budget.”1MIT. Major Tax Impact on MIT and Its Mission Endowment distributions fund a large share of MIT’s operating spending, including faculty positions, financial aid, research programs, and facility maintenance.
MIT’s spending policy blends 80% of the prior year’s distribution (adjusted for inflation) with 20% of a 5.1% target payout rate applied to the endowment’s market value. In practice, MIT distributes roughly $2 billion or more each year from the endowment to support operations. Every dollar paid in excise tax is a dollar that cannot flow into those distributions.
Under the old 1.4% rate, the tax was manageable at MIT’s scale. At 8%, it becomes a line item that forces real trade-offs on how the university absorbs the cost, whether by reducing spending, growing the endowment faster, or seeking legislative change.
Why the Tax Exists
Before 2017, private college endowments paid no federal tax on their investment earnings, in line with other nonprofit organizations. The Tax Cuts and Jobs Act of 2017 created Section 4968 of the Internal Revenue Code, imposing the first federal excise tax on the investment income of the wealthiest private colleges and universities.6Congress.gov. College and University Endowments: Overview and Tax Policy Options The original rate was a flat 1.4% on net investment income, modeled after the excise tax that private foundations have paid under Section 4940 since 1969. The policy argument was that institutions holding tens of billions of dollars in investment assets, and growing that wealth in capital markets, should contribute something to the federal treasury despite their educational tax exemption. The 2025 law kept that structure and sharpened it.