Cost Segregation in Massachusetts: State Tax Rules (2026)

Massachusetts decouples from federal bonus depreciation, so a cost segregation study produces a much smaller first-year state deduction than the federal return suggests.

The state also imposes a 4% surtax on taxable income above roughly $1,000,000, indexed annually. That surtax interacts with large one-time deductions in a way that makes timing genuinely valuable rather than merely convenient.

Massachusetts Does Not Follow Bonus Depreciation

Massachusetts has decoupled from the federal bonus depreciation allowance under IRC Sec. 168(k). Depreciation for state purposes is computed under MACRS without the additional first-year allowance.

Reclassified components still depreciate over their shorter recovery periods, so a study accelerates state depreciation meaningfully relative to a 27.5-year or 39-year schedule. It simply does not produce a single large first-year state deduction.

Massachusetts and federal basis therefore diverge from the first year and must be tracked separately through disposition.

The Surtax Changes the Timing Calculus

Massachusetts imposes a surtax of 4% on the portion of annual taxable income exceeding a threshold near $1,000,000, indexed for inflation, on top of the base individual rate.

This creates a genuine bracket to manage, which is unusual in a flat-rate state. Income above the threshold faces a materially higher combined rate.

The surtax is computed on annual taxable income, so a one-time spike, such as a property sale or a business exit, can push a household above the threshold for a single year. Deductions that reduce income in that specific year are worth more than deductions in ordinary years.

For an investor anticipating a large gain, running a cost segregation study on another property in the same year to shelter income below the threshold is a legitimate and valuable timing strategy. Because the study can be run as a look-back with Form 3115 on property already owned, the deduction can be placed in the year it is needed rather than the year of acquisition.

Capital Gains Treatment

Massachusetts taxes long-term capital gains at the base individual rate, with certain short-term gains taxed at a higher rate. The surtax applies on top where total taxable income exceeds the threshold.

A property sale generating $1,800,000 of gain will push most households well past the surtax threshold. The combined state rate on the excess is meaningfully higher than on ordinary years, which strengthens the case for either installment structuring under IRC Sec. 453 or a 1031 exchange under IRC Sec. 1031.

Because Massachusetts depreciation is lower than federal depreciation, Massachusetts basis is higher and Massachusetts gain is lower. This partially offsets the surtax exposure and should be computed rather than assumed.

Passive Loss Rules

Massachusetts generally follows the federal passive activity determination, so real estate professional status and the aggregation election carry into the state computation.

The state loss will be smaller because of the depreciation modification, but the character of the loss follows federal treatment. This is more favorable than category-income states.

Worked Example: Timing Around the Surtax

An investor sells a Boston-area property in the current year, generating $2,300,000 of Massachusetts taxable gain. Household income including the gain is approximately $2,650,000, placing roughly $1,650,000 above the surtax threshold.

The 4% surtax on that excess is approximately $66,000 on top of base tax.

The investor also owns two rental properties acquired in 2022 and 2023 that have never been studied. Look-back cost segregation studies filed with Form 3115 produce a combined Sec. 481(a) adjustment of approximately $486,000 federally.

For Massachusetts, the adjustment is smaller because bonus depreciation is added back, but the reclassification to five-year and 15-year schedules still produces a catch-up of roughly $214,000 for state purposes.

That $214,000 reduces income subject to the surtax, saving approximately $8,560 in surtax alone plus base tax on the same amount.

Federally, the $486,000 deduction against a 37% rate is worth roughly $180,000.

The key point is that the deduction was placed in the year it was worth the most. Had the studies been run in 2022 and 2023 when the properties were acquired, the deductions would have landed in ordinary years and the surtax exposure in the sale year would have been unmitigated.

State conformity provisions are amended frequently and the mechanics below should be confirmed against the current year instructions before filing.

Planning Points

Track Massachusetts and federal basis separately from acquisition. The divergence is permanent and reconstructing it at sale is expensive.

Treat the surtax threshold as a planning target. Deductions are worth 4% more when they land in a year that crosses it.

Use look-back studies deliberately. The ability to place a large deduction in a chosen year through Form 3115 is the most useful timing tool available to a Massachusetts investor.

For anticipated large gains, model installment sale treatment under IRC Sec. 453 against a 1031 exchange, since spreading gain across years can keep each year below the surtax threshold.

Frequently Asked Questions

Does Massachusetts allow bonus depreciation?

No. Massachusetts has decoupled from the federal bonus depreciation allowance under IRC Sec. 168(k). State depreciation is computed under MACRS without the additional first-year allowance, so federal and Massachusetts basis diverge immediately.

What is the Massachusetts millionaires tax?

A 4% surtax on the portion of annual taxable income above a threshold near $1,000,000, indexed for inflation, applied on top of the base individual rate. Because it is computed annually, one-time income spikes such as property sales are heavily exposed to it.

Can I time a cost segregation study to reduce the surtax?

Yes, and this is the most useful timing tool available. A look-back study filed with Form 3115 on a property you already own places the catch-up deduction in the current year, which lets you offset a gain year rather than an ordinary year.

Is cost segregation worth it in Massachusetts?

Yes. The federal benefit is unaffected, and even without bonus depreciation the state benefit from reclassifying to five-year and 15-year schedules is substantial relative to 27.5 or 39 years.

Does Massachusetts follow federal passive loss rules?

Generally yes. Real estate professional status and the aggregation election carry into the Massachusetts computation, so the character of the loss follows federal treatment. Only the amount differs, because of the depreciation modification.

Cost Segregation in Massachusetts: Decoupling and the Millionaires Tax