The Massachusetts Millionaires Tax and Selling Your Business: How the 4% Surtax Hits Your Sale Proceeds (And Legal Ways to Plan Around It)

If you own a business in Massachusetts worth $2 million, $5 million, or more, there's a number you need to burn into your brain: 4%. That's the additional surtax Massachusetts now levies on annual income exceeding $1 million, thanks to the so-called "Millionaires Tax" (Question 1) that voters approved in November 2022. When you sell your business, the gain almost certainly pushes you past that threshold in a single tax year — and the Massachusetts Millionaires Tax and selling your business is a collision that can cost you hundreds of thousands of dollars if you don't plan ahead.

The good news: this isn't a surprise. It's a known variable. And known variables can be planned around.

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How the Extra 4% Actually Works When You Sell a Business in Massachusetts

Article 44 of the Massachusetts Constitution imposes an additional 4% income tax — technically a surtax, meaning it stacks on top of the tax you already owe — on the portion of annual taxable income above a set threshold. The state's flat income tax is 5%, so every dollar above the line is taxed at 9%.

The threshold started at $1 million in 2023 and rises with inflation each year:

Tax year Thresholds: 

2023: $1,000,000

2024: $1,053,750

2025: $1,083,150

2026: $1,107,750

Here's where it gets painful for business owners. When you sell your company, the entire capital gain is recognized as income in the year the sale closes. Sell a $3 million business with a $500,000 basis and you have $2.5 million in gain. After subtracting the 2026 threshold, roughly $1.4 million of that gets hit with the extra 4% — about $56,000 in state tax you wouldn't have owed before 2023. On a $7 million exit, the extra 4% alone can run past $200,000.

And that's just the state layer. You're still paying federal capital gains tax (typically 20% for high earners), the 3.8% Net Investment Income Tax, and the base 5% Massachusetts rate. Stack it all up and a Boston-area owner selling a company can face a combined rate approaching 33% on the dollars above the threshold.

A Real-World Scenario: Selling a $4M Service Business on Route 128

Say you own a $4 million IT services firm in Waltham. You've built it over 18 years. Your adjusted basis is $300,000. You sell via an asset sale, and after allocation your long-term capital gain is approximately $3.2 million.

The rough tax math:

• Federal capital gains tax (20%): $640,000
• Net Investment Income Tax (3.8%): $121,600
• Massachusetts base income tax (5%): $160,000
• Massachusetts extra 4% (on ~$2.09M above the threshold): $83,690

Total estimated tax: approximately $1,005,000. The extra 4% accounts for nearly $84,000 of that — money that simply didn't exist as a liability before 2023.

That's $84,000 you could have kept with better timing or structure. Which brings us to the part that actually matters.

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Legal Ways to Plan Around the Massachusetts 4% Surtax on Your Business Sale

Let's be clear: nobody is suggesting anything gray here. These are legitimate, well-established strategies that tax attorneys and CPAs use every day. But they require advance planning — often 12 to 36 months before your sale closes.

1. Installment Sales (IRC §453)

Instead of recognizing the entire gain in one year, you can structure the sale so the buyer pays over multiple years. If you spread $3 million in gain across three tax years, you might keep each year's income below — or closer to — the $1 million threshold. This reduces or eliminates the surtax exposure. The tradeoff: you're carrying credit risk on the buyer, and you need to negotiate terms carefully.

2. Opportunity Zone Reinvestment

If you reinvest capital gains into a Qualified Opportunity Zone Fund within 180 days of the sale, you can defer the gain. Massachusetts currently conforms to the federal Opportunity Zone provisions. There are designated OZ areas in Worcester, parts of Boston, and other Massachusetts cities. This doesn't eliminate the tax, but it defers it — and if you hold for 10+ years, gains on the new investment are tax-free.

3. Charitable Planning (CRTs and Donor-Advised Funds)

Charitable Remainder Trusts can be powerful if philanthropy is already part of your plan. You contribute appreciated assets to the trust before the sale, the trust sells tax-free, and you receive an income stream. This can dramatically reduce the gain recognized in any single year. Donor-Advised Funds can also create meaningful deductions in the year of sale to offset income.

4. Residency Planning

This is the blunt instrument. Massachusetts taxes you as a resident on all income, regardless of where it's earned. Some business owners consider establishing residency in a state with no income tax — New Hampshire is 45 minutes north — before a sale. But Massachusetts is aggressive about auditing residency changes near liquidity events. If you go this route, it needs to be genuine, well-documented, and initiated well before the sale process begins. Half-measures get caught.

5. Entity Structure and Sale Type Optimization

Whether you sell assets or stock, whether your entity is an S-corp or C-corp, and how the purchase price is allocated across asset classes — all of these affect how and when gain is recognized. Optimizing your entity structure before going to market can yield six-figure tax savings. This is forensic-level work, and it's one reason we do deep financial recasting at Nova Exit Partners before listing any business.

The Biggest Mistake: Waiting Until the LOI Is Signed

Most business owners start thinking about tax strategy when a buyer slides a Letter of Intent across the table. By then, your options have already narrowed dramatically. You can't do an installment sale if the buyer wants to close in 60 days and pay cash. You can't move to New Hampshire three weeks before closing without inviting an audit. You can't set up a CRT after you've already signed a purchase agreement.

The owners who keep the most from their exit are the ones who start planning 18 to 24 months before they sell. That's not a sales pitch — it's tax math.

Start With What Your Business Is Actually Worth

Before you can plan around the surtax, you need to know your probable sale price. Everything — installment sale feasibility, charitable planning thresholds, residency timing — flows from that number.

At Nova Exit Partners, we build detailed valuations for Greater Boston business owners that incorporate real market multiples, buyer demand in your industry, and the specific financial profile of your company. Erik Kretschmar has personally sold four of his own businesses, so the guidance you get isn't theoretical — it's built on experience.

If you're even considering a sale in the next one to three years, the time to understand your exposure to the Massachusetts Millionaires Tax is now — not the week you get an offer.

Get your free business valuation and we'll walk you through what your exit could look like after taxes — so there are no surprises when it matters most.