The IRS Fixed One Penalty in July. It Didn't Fix the One That Catches Traders

Earlier this month, the IRS rolled out something it doesn't do often: an automatic penalty-relief process that requires no phone call, no form, and no request. It's a genuine simplification — and it's easy to read a headline about it and assume the penalty risk around estimated taxes is handled. It isn't. The rule the IRS just automated covers a different penalty than the one most likely to catch an active trader off guard this year.

Two penalties, not one

The IRS's new Automatic Exemption from Penalty (AEP), announced July 8, 2026, replaces the older "First Time Abate" process. For taxpayers with a clean three-year compliance history, it now automatically waives penalties in three specific categories: failure to file, failure to pay, and failure to deposit. That's a real, useful change for anyone who's ever missed a single deadline after years of filing on time.

What AEP does not cover — and doesn't claim to — is the underpayment-of-estimated-tax penalty under Internal Revenue Code section 6654. That's a structurally different penalty, assessed when you haven't paid enough tax throughout the year as income was earned, regardless of whether you eventually file and pay in full by the deadline. The IRS treats these as separate categories for a reason: one is about missing a deadline, the other is about paying too little, too late.

Why this matters for traders

Wage income has taxes withheld automatically, paycheck by paycheck, so most W-2 employees rarely think about this penalty at all. Trading gains work differently. Short-term capital gains — which cover most active options and stock trading, since it applies to anything held under a year — get taxed at ordinary income rates and are not subject to any withholding. If you had a strong first half of 2026, that income has had nothing withheld against it, and the IRS expects you to have been paying toward it in estimated installments along the way — not catching up all at once in April 2027.

The Q3 2026 estimated payment is due September 15, 2026 — about eight weeks from now. It's the third of four unevenly-spaced payment periods (mid-April, mid-June, mid-September, and mid-January), and it specifically covers income earned from June through August. The name "Q3" is a little misleading: it doesn't line up with calendar Q3 and it isn't optional just because a lot of the year's income might have come earlier, in Q1 or Q2.

The safe harbor: how to avoid the penalty entirely

You generally won't owe this penalty at all if either of the following is true:

• You owe less than $1,000 in tax after subtracting withholding and credits, or
• Your total withholding and estimated payments for the year add up to at least 90% of what you'll owe for 2026, or 100% of what you owed for 2025 (110% if your 2025 adjusted gross income was over $150,000, or $75,000 if married filing separately) — whichever of those two figures is smaller.

That second bullet is the one that matters most for traders. If your 2025 tax bill was modest but 2026 has been a much bigger trading year, the 100%/110%-of-last-year safe harbor can be a meaningfully lower bar to clear than trying to estimate 90% of a still-unknown 2026 total. It's worth running both numbers rather than assuming the higher-income year automatically means a higher required payment.

What the penalty actually costs if you miss it

If you fall short of the safe harbor, the IRS calculates the penalty like compounding interest on the shortfall rather than a flat fine — it's based on the size of the underpayment, how long it went unpaid, and the IRS's published quarterly underpayment rate, which is 7% for the July-September 2026 quarter (up from 6% the prior quarter), per IRS.gov's quarterly interest rate bulletin. That rate resets every quarter, so a shortfall left unpaid into Q4 could accrue at a different rate than the one in effect right now.

A tool for uneven income

One useful tool for traders whose income arrives unevenly across the year — a big rally in Q1, a quiet Q3 — is the annualized income installment method on IRS Form 2210. Instead of assuming income was earned in equal amounts every quarter (the default assumption), it lets you match your estimated payments to when the income actually showed up, which can reduce or eliminate a penalty that a flat, evenly-spaced calculation would otherwise generate.

The mid-year check worth doing now

With eight weeks of runway before September 15, this is a reasonable moment to add up year-to-date realized gains, compare them against total withholding plus estimated payments made so far, and see which side of the 90%/100%/110% safe harbor you're actually on. That's a straightforward exercise, though how it applies to your specific filing situation depends on facts a general educational article can't know — your income mix, state tax exposure, and prior-year numbers all matter. That's exactly the kind of judgment call a tax professional is positioned to make, and this article isn't.

This article is educational commentary on public tax rules and deadlines, not personalized investment, trading, or tax advice.