Trust Accounting and Fiduciary Taxation

Fiduciary income tax rules under Subchapter J of the Internal Revenue Code are highly compressed. For tax year 2026, a non-grantor complex trust hits the top 37% ordinary income tax bracket at just $16,000 of accumulated taxable income, and the top 20% long-term capital gains bracket at $16,250. In addition, the 3.8% Net Investment Income Tax (NIIT) under IRC §1411 applies to undistributed net investment income above these same low thresholds. Because of this compression, strategic coordination between trust accounting and tax planning is necessary to avoid confiscatory taxation.

To manage fiduciary taxes, you must distinguish between two separate concepts:

Trust Accounting Income (TAI)

TAI is the fiduciary concept of income determined by the trust instrument and state law under the Uniform Fiduciary Income and Principal Act (UFIPA). TAI defines what is allocated to the current income beneficiaries versus the remainder beneficiaries. By default under the UFIPA, ordinary receipts (interest and dividends) are classified as income, realized capital gains are allocated to principal (corpus), and administration fees (such as trustee and tax preparation fees) are split 50/50 between income and principal.

Distributable Net Income (DNI)

DNI is a tax concept defined under IRC §643 that caps the fiduciary’s income distribution deduction and determines the maximum taxable amount (and character) of distributions in the hands of the beneficiaries. DNI is calculated by taking the trust’s taxable income (before the distribution deduction and personal exemption) and subtracting capital gains allocated to principal, then adding back tax-exempt interest (net of allocable expenses).

Fiduciary taxation operates under a conduit system, utilizing the Income Distribution Deduction (IDD) under IRC §651 (for simple trusts) and IRC §661 (for complex trusts):

• Simple Trusts: Must distribute all TAI currently, cannot make charitable contributions, and cannot distribute principal. The trust deducts the distributed income up to the DNI limit. The beneficiary reports this income on their individual tax return, and the trust is typically taxed only on retained capital gains.
• Complex Trusts: May accumulate income, distribute principal, or make charitable contributions. The trust receives a deduction for actual distributions made during the tax year (or within the first 65 days of the following year under the IRC §663(b) election).

Under IRC §67(e), expenses that are unique to trust administration—including corporate trustee fees, fiduciary accounting fees, and trust legal fees—are fully deductible above-the-line. They are not subject to the suspension of miscellaneous itemized deductions. Because beneficiaries are often in lower tax brackets than the trust’s top $16,000 threshold, shifting taxable income from the trust to the beneficiaries via discretionary distributions is the primary tax-minimization strategy for non-grantor trusts.