Income vs. Principal: The Distinction Every Trustee Must Understand
This article explains why the distinction between trust income (what the trust earns) and principal (what the trust owns) is central to a trustee’s fiduciary duty and personal liability risk. It walks through default rules under the Uniform Principal and Income Act, how trust documents can override those rules, and how receipts and expenses must be allocated between income and principal to treat income and remainder beneficiaries impartially. It also highlights the tax consequences of misclassification and stresses reading the trust instrument first, consulting state law, and documenting decisions carefully—seeking professional advice when the answer isn’t clear.
TRUST AND ESTATE PLANNING
3/18/20264 min read
If you're serving as a trustee, one of the first concepts you need to wrap your head around is the difference between income and principal. It sounds simple enough on the surface, income is what the trust earns, and principal is what the trust owns. But in practice, the classification of receipts and disbursements between income and principal is one of the most consequential decisions a trustee makes, and getting it wrong can expose you to personal liability.
Think of it this way. The principal, sometimes called the corpus, is the body of the trust. It's the collection of assets that were originally placed into the trust by the grantor: real estate, stocks, bank accounts, business interests, and any other property that was transferred. Income is what those assets generate over time: rent from the property, dividends from the stocks, interest from the bank accounts, and royalties from intellectual property.
Why does this distinction matter so much? Because many trusts have different beneficiaries for income and principal, and the classification directly determines who gets what. A very common trust structure gives one person, often a surviving spouse, the right to receive all trust income during their lifetime. When that income beneficiary dies, the remaining principal passes to a different set of beneficiaries, typically children or grandchildren. This is called a life estate arrangement, and it creates an inherent tension between the income beneficiary, who wants maximum current income, and the remainder beneficiaries, who want the principal preserved and growing.
If you as trustee classify something as income when it should properly be treated as principal, you're effectively taking money from the remainder beneficiaries and giving it to the income beneficiary. Do the reverse, and you're shortchanging the income beneficiary for the benefit of the remainder holders. Either way, you've breached your fiduciary duty of impartiality, the obligation to treat all beneficiaries fairly and in accordance with the terms of the trust.
The Uniform Principal and Income Act, which has been adopted in some form by most states, provides the default rules for how trustees should classify receipts and expenses. Under the Act, items like rent, cash dividends, interest payments, and business income from pass-through entities are generally treated as income. On the other side, capital gains from the sale of trust assets, stock splits, stock dividends, insurance proceeds for lost or damaged trust property, and proceeds from the sale of real estate are generally treated as principal.
But here's where it gets complicated, and where many trustees get tripped up. The trust document can override these default statutory rules. If the trust instrument specifically provides that capital gains are to be treated as income, or that a certain percentage of principal may be distributed annually regardless of income, those provisions control. The trust document is always your primary authority. The state statute only fills in the gaps where the document is silent. This means your first step as trustee should always be reading the trust instrument carefully to identify any income and principal provisions that differ from the default rules.
Expenses follow a similar split, and getting this right matters just as much as getting the receipt classification right. Ordinary, recurring expenses related to the ongoing administration of the trust, accounting fees, trustee compensation, investment advisory fees, property management costs, insurance premiums on trust property, and routine maintenance, are typically charged against income. Extraordinary or non-recurring expenses, capital improvements to trust property, attorney fees for defending the trust against litigation, costs related to the sale or purchase of trust assets, and environmental remediation costs, are typically charged against principal.
Some expenses get split between income and principal. Trustee fees, for example, are often allocated partially to each. Tax preparation fees for the trust's Form 1041 return may also be split. The trust document may address this directly, and if it doesn't, the Uniform Principal and Income Act provides a default allocation.
The tax implications of getting this wrong add another layer of consequence. Trust income is reported on Form 1041 and is either taxed at the trust level or passed through to beneficiaries on Schedule K-1. The classification between income and principal directly affects how much distributable net income, or DNI, the trust has, and DNI is the mechanism that determines how much tax is borne by the trust versus the beneficiaries. If you misclassify receipts, you could be generating incorrect tax returns, miscalculating DNI, and issuing wrong K-1s to beneficiaries.
The compressed trust tax brackets make this even more consequential. For 2026, the highest federal income tax rate of 37 percent kicks in at just over $15,000 of taxable income for trusts and estates, compared to over $600,000 for a single individual filer. This means that keeping income inside the trust when it should be distributed, or distributing principal when income should be retained, can create significant and unnecessary tax liability.
Many modern trusts include a provision giving the trustee the power to adjust between income and principal, or to recharacterize receipts from one category to the other. This power, often called a unitrust conversion or a power to adjust, is designed to give the trustee flexibility to balance the competing interests of income and remainder beneficiaries, especially in low-interest-rate environments where traditional income-producing investments may not generate enough cash for the income beneficiary's needs. If your trust includes this power, understand its scope and limitations before exercising it, as it can have both fiduciary and tax consequences.
When in doubt, go back to the trust document first. Then look at your state's version of the Principal and Income Act. If the answer still isn't clear, get professional guidance from an attorney or CPA who understands trust accounting before making the allocation. The cost of a consultation is a fraction of the cost of fixing a misclassification after distributions have been made, tax returns have been filed, and beneficiaries have already received the wrong amounts. Document your reasoning for every significant allocation decision in your trustee records, if a beneficiary ever challenges your classification, those contemporaneous records are your best defense.