In Back Bay, the Tax Bill Follows the Owner, Not the Condo

Take two condos in the same Back Bay building, assessed at the same value, on the same floor. One is taxed at full value. The other has about $351,000 of its value taken out before the rate applies. The building, square footage and assessment are identical. The only difference is that someone owns the second unit and lives in it.

Boston's residential exemption causes this split. Most buyers first run into it at a bad moment, partway through a transaction, when the annual tax figure for a unit turns out to reflect the seller's situation rather than their own. If the seller lived there, the figure includes a credit an investor buyer won't get. If the seller rented the unit out, the figure leaves out a credit an owner-occupant buyer may be able to claim. In both cases, the number attached to the unit describes the previous owner.

The exemption is a fixed dollar amount, so its value depends on the unit's price

The City of Boston describes the exemption as taking a portion of a home's value out of taxation for owners who occupy the property as their principal residence. In fiscal year 2026, it saved qualifying homeowners $4,353.74, and the City budget notes it was set at the maximum 35% of average assessed residential value. At the FY26 residential rate of $12.40 per $1,000, that saving equals roughly $351,000 of assessed value removed from the tax base.

Each qualifying home gets the same dollar figure, whatever it's worth. The table applies the FY26 rate to three assessed values. These are illustrative calculations, not actual tax accounts.

At Back Bay price points, the exemption doesn't decide whether a unit is affordable to carry. It does create a fixed annual gap of $4,353.74 between owner-occupied and non-owner-occupied units, and that gap is the same whether the unit is a one-bedroom on Marlborough Street or a full floor on Commonwealth Avenue. For an investor modeling a rental, the full-rate bill is the real carrying cost. A seller's bill that includes the exemption understates it by that amount.

One limit applies at the low end. The City says no parcel can be taxed on less than 10% of its assessed value, with exceptions for certain residents facing physical infirmity or financial hardship. Under the FY26 numbers, that floor only applies to homes assessed below about $390,000, which is well under most of the Back Bay condo market.

The gap has grown every year since FY18

The owner-versus-investor difference isn't a fixed rule of the market. It's reset every December, and the City's own rate history shows the direction it has moved.

• FY18: $2,538.47 exemption saving, $10.48 residential rate
• FY22: $3,305.20 saving, $10.88 rate
• FY24: $3,610.53 saving, $10.90 rate
• FY25: $3,984.21 saving, $11.58 rate
• FY26: $4,353.74 saving, $12.40 rate

From FY18 to FY26, the saving rose about 72%. That means the annual cost difference between two otherwise identical units, one occupied by its owner and one rented out, rose by the same amount. Over the same years, the residential rate moved within a narrow range before rising in FY25 and FY26.

The rate increase comes from commercial real estate. City budget documents explain that both residential and commercial rates rose in FY26 because overall property value growth slowed, "due to lingering high vacancy rates in the commercial office and lab markets." Using Jones Lang LaSalle data, the City put citywide office vacancy at 23.6% in the third quarter of 2025, about double pre-pandemic rates, with Downtown at 20.0%.

Boston has to raise a set amount of money, and state law fixes how much of it can fall on commercial property. When office values fall and home values rise, more of the total shifts to residential owners. WBUR reported that, according to the Wu administration, residential values rose 2% over the prior year while commercial values fell 6%. For FY26, residential taxpayers paid 46% of the levy and commercial, industrial and personal property paid 54%. At the December 2025 vote, Council President Ruthzee Louijeune said "we're coming very close to a point where residents are shouldering 50% of the total property taxes that are collected by the city."

The exemption itself is paid for within the residential class. Raising it lowers bills for owner-occupants and adds to the share carried by everyone else in the class, which includes investor-owned condos. So as the residential share of the levy rises, the exemption's dollar value and the full-rate bill on a rental unit tend to rise together.

The December 2025 vote used every option the City has

On December 10, 2025, the Boston City Council voted unanimously to set commercial taxes at 175% of the residential burden and to approve the 35% owner-occupant exemption. Both are the maximums state law allows. WBUR reported that even with both maximums, homeowners still faced a 13% increase, about $780 on average. The City's relief calculator also describes a 13% increase for the average single-family home receiving the exemption. Because of how the billing calendar works, WBUR also reported that residents would see a 26% jump in January, as the increases from two fiscal years overlapped, before settling at 13%.

Going past those limits takes action by the Legislature. Mayor Michelle Wu has proposed temporarily raising the commercial share to 181% for three years. WBUR reported that the change would have held residents to a 9% increase instead of 13%. On January 15, 2026, the State Senate rejected an amendment mirroring that proposal by 5 to 33, according to the Boston Globe. The Senate passed its own tax relief bill 37 to 1 that day. The Legislature's page for S2917 lists no House action after the Senate vote.

City budget documents say FY27 tax rates will be set in December 2026. As of October 2026, no FY27 residential rate or exemption amount has been published. Anyone pricing a Back Bay purchase for next year is working from FY26 figures and from the trend in the list above.

Buyers who closed early in 2026 may be eligible sooner

One change does help recent buyers. The City's Assessing Department says a recent home rule petition expanded the exemption, so homeowners who recorded a deed at the Suffolk County Registry of Deeds and occupied the property as their principal residence between January 1 and June 30, 2026, may qualify for FY27. Before this change, eligibility depended on owning and occupying the home on January 1. Owners who already met that test are not affected.

The timing works like this:

1. The City applies the exemption to the third-quarter tax bill, which goes out in late December.
2. To have the credit appear on that bill, the City recommends filing by mid-October.
3. The final FY27 filing deadline is April 1, 2027.
4. A person can qualify on only one parcel in the city, and filing does not postpone tax payments.

The application asks for a Social Security number, which the City says it uses only to confirm the tax filing from the property's address. Questions go to the Taxpayer Referral and Assistance Center at 617-635-4287.

For a buyer who closed on a Back Bay condo last spring and moved in, the third-quarter bill is the first place the new owner's status shows up. Until then, the bill can still reflect the seller's status.

Quick answers

Does the exemption transfer with the unit when it sells? No. It's tied to an owner who occupies the property as a principal residence, so each new owner qualifies or doesn't based on their own circumstances.

Can an investor-owned rental condo receive it? A non-owner-occupied unit doesn't meet the occupancy condition, so it's taxed at full assessed value.

What will the FY27 exemption be? It hasn't been announced. The FY26 saving was $4,353.74, and FY27 rates are scheduled to be set in December 2026.

Does this article tell me what I'll owe? No. The figures above show how the system works using FY26 numbers. Your actual bill depends on your assessment, the FY27 rate and your eligibility, which Boston Assessing determines.

If you're comparing Back Bay condos as a future owner-occupant or as an investor, it helps to know which tax figures you're looking at. Colin Bayley and the Bayley & Natoli team can compare a unit's current bill with what it would likely be under your ownership, using the latest published rates, before you make an offer. Request a Home Valuation & Market Plan and we'll put that comparison in writing for the units on your list.

This article is general information, not legal, tax or financial advice. Consult a qualified professional about your situation.