The 65-Day Rule for trusts gives trustees until March 6th to make a distribution that counts toward the prior tax year — a simple strategy that can meaningfully reduce the tax burden on trust income. If you are a trustee or a trust beneficiary, here is what you need to know before the deadline arrives.

Trustees might not know this rule exists. The ones who do may wait too long to use it. 

Under Section 663(b) of the Internal Revenue Code, an estate or complex trust can treat a distribution made within the first 65 days of the new tax year as if it occurred on December 31st of the prior year. For a calendar-year trust, that window runs from January 1st through March 6th. 

That’s the deadline. It doesn’t move. 

What Is the 65-Day Rule for Trusts? 

The 65-Day Rule gives trustees additional time, after the tax year has ended, to decide how much income to distribute from a trust while still having that distribution count toward the prior year. Rather than estimating in late December, trustees can review the trust’s actual income in January or February and make a more informed decision. It sounds like a small procedural detail. The tax savings it can generate are anything but. 

Why Does It Matter? Trust Tax Rates vs. Individual Tax Rates 

Trusts are taxed punitively compared to individuals. In 2025, a trust reaches the top federal income tax bracket of 37% when taxable income exceeds $14,450. A single individual doesn’t hit that same rate until income exceeds $626,350. That compression is the entire reason this strategy exists. If trust income can be distributed to a beneficiary in a lower tax bracket, the family pays less tax on the same dollars. The 65-Day Rule simply extends the window to make that call, when the numbers are known, not estimated. It’s a practical fix for a real problem: trustees shouldn’t have to guess in December. 

What Should Trustees Consider Before Making a Distribution? 

The 65-Day Rule isn’t a blanket win. There are three factors every trustee should work through before acting. 

Distributions Mean Giving Up Control

Trusts are often structured so the trustee can manage how and when a beneficiary receives money. Once income is distributed, that discretion is gone. If the trust document or family circumstances call for keeping funds inside the trust, pursuing a tax deduction may not be worth the trade-off. 

The Beneficiary’s Full Income Matters

A distribution that looks efficient at the trust level can create problems at the individual level, pushing a beneficiary over AGI thresholds, triggering state income taxes, or reducing deductions. The analysis needs to account for both sides. 

Watch for IRMAA and Trust Distributions

IRMAA, the Income-Related Monthly Adjustment Amount, is a surcharge on Medicare Part B and Part D premiums triggered when income exceeds certain thresholds. Because IRMAA is calculated based on income from two years prior, a trust distribution that spikes a beneficiary’s income this year can increase their Medicare costs in 2027. For clients in or near retirement, this is often the most consequential part of the analysis. 

Who Should Be Thinking About the 65-Day Rule? 

• You serve as a trustee of an estate or complex trust 
• You are a beneficiary of a trust that generated meaningful income last year 
• Your trust is in a higher tax bracket than its beneficiaries 
• You or a beneficiary are approaching or currently on Medicare 

The Window Closes March 6th 

There’s no extension, no workaround after the fact. If the math supports a distribution and the broader circumstances align, the decision needs to be made before March 6th. Not sure if the 65-Day Rule applies to your situation? Our team can walk you through the analysis, across the trust, the beneficiary’s income, and the full financial picture, before the deadline arrives. 

At Winthrop Wealth, tax planning strategy doesn’t happen in isolation. It’s part of how we look at your entire financial picture. With you, for life. 

Source: Kenneth J. Dean, CPA, CFP®, CFA, MST — winthropwealth.com