Why does the trust pay tax on income instead of the beneficiary?

Short answer: because the IRS treats an irrevocable trust as a SEPARATE TAXPAYER from both the grantor and the beneficiary. The trust legally owns the assets, so it earns the income, and it pays the tax — unless and until the income is actually distributed to the beneficiary (then the beneficiary picks up the tax), or unless the trust is a "grantor trust" (then the grantor pays).

The three possibilities

The default rule

When you set up an irrevocable trust and the trust ACCUMULATES income (does not distribute it to the beneficiary that year), the trust pays the tax. The beneficiary has not yet received the income, so she has not realized it.

Why this hits special-needs planning hard

For most beneficiaries, the trustee strategy is "distribute up to DNI to push tax to the lower-bracket beneficiary." But a special-needs beneficiary who receives distributions may LOSE Medicaid eligibility. So the trustee accumulates income inside the trust — which means it gets taxed at the compressed trust schedule (top bracket at only $15,650 of income).

This is an unavoidable cost of preserving Medicaid eligibility, but it can be mitigated by:

1. Investing for long-term capital gains and qualified dividends rather than interest income — preferential rates apply to trusts too
2. Distributing payments DIRECTLY to providers (medical, housing, education) — these often do not count as beneficiary income for SSI / Medicaid
3. Using an ABLE account alongside the SNT for some expenses, since up to $19,000/year (2025) can be contributed without affecting Medicaid

The grantor trust exception

If the trust agreement gives the grantor any of these retained powers, ALL income is taxed BACK to the grantor personally, regardless of where the income physically goes:

Sophisticated planners INTENTIONALLY trigger one of these (typically the swap power under 675) to create an Intentionally Defective Grantor Trust (IDGT). The trust is "defective" for income-tax purposes (grantor pays tax) but VALID for estate-tax purposes (assets are out of the grantor estate). The grantor effectively makes additional tax-free gifts by paying the income tax personally.

Read more in our trust income taxation article.