The lab glut and the tax base

Updated September 22, 2026

What's happening

Somerville bet its commercial tax base on life science buildings, and the tenants never came. New growth revenue — the property tax a city is allowed to add on top of Proposition 2½'s cap because of new construction — peaked at $17.7 million in FY24, fell to $7.8 million in FY26, and is projected at about $5 million for FY27, a level Finance Director Ed Bean expects to persist for three years (April 14 Council). That is roughly a 75% drop from the peak (June 4 Council).

The cause is specific and countable. Of Somerville's 10 life science buildings, Chief Assessor Frank Golden reported in April, only five are stabilized, with 1.9 million square feet vacant. Values on commercial and lab property have now declined three years running; six buildings sit at roughly 60% complete and weather-tight; most owners have filed abatements and three have been settled (June 9 Finance). Converting them isn't a way out: Mayor Jake Wilson told the Council that limited windows and specialized air handling make retrofitting labs to residential or other uses impractical.

The consequence a reporter should watch for is the November classification vote, when the Council sets tax rates for FY27. That is the meeting where a shrinking commercial base stops being an assessor's slide and starts being a number on a homeowner's bill.

The story

The regional picture

Somerville isn't alone, which is exactly the problem — there is no local fix for a regional glut. Just over one-third of all life sciences space in Greater Boston, the country's largest lab market at 56.7 million sq ft, was vacant at the end of the third quarter of 2025, per Cushman & Wakefield. The worst submarket is the "urban ring" — Watertown, Somerville, Allston, Brighton, Fenway — where roughly 55% of 11.7 million sq ft was available. More than two-thirds of the region's 1.6 million sq ft of leasing through three quarters went to Cambridge (Bisnow, October 9, 2025).

Colliers research director Jeff Myers on how it happened: "I don't think people really recognize, just on the macro scale, how much new construction we've had in communities like Somerville, Watertown and places like that... We really, really, really built a lot." Demand collapsed with venture funding — Massachusetts biotech VC totaled $2.75 billion in the first half of 2025, down 17% year over year, per MassBio. JLL executive managing director Bob Richards was blunt: "there's a sizable portion of the existing lab inventory that is never going to be leased up as lab space, and it's going to need to be repurposed... I don't see the market improving significantly in the next 18 to 24 months."

Bisnow named the Somerville buildings: US2's 196,000 sq ft 10 Prospect Street in Union Square, no leases announced since it opened in 2024; CV Properties and Cannon Hill's 336,000 sq ft Boynton Gateway, opened in late 2024, same; Leggat McCall's 808 Windsor at Boynton Yards, unleased, while its 101 South next door filled up. Golden's own framing in April: 15 million sq ft of lab space vacant across Greater Boston against a market appetite of about 2 million sq ft a year.

How it hits the budget

The April 14 financial condition report is the document that lays out the chain. Bean opened the FY27 process with a $4.5 million gap between projected revenue and level-service spending, up from $3 million the year before. The city could raise about $12.7 million in additional revenue, $11.9 million of it property taxes including the high school debt exclusion — and nearly everything else was falling: parking fines down $400,000, meals tax flat, investment income sliding as rates came down, meter receipts down about $200,000, building permits short roughly $500,000. State aid under the governor's proposal would rise $739,102 net of assessments, 2.3%, and Bean noted state aid to Somerville remains below FY2002 levels in real dollars — $55.8 million now versus $61.8 million then.

The FY27 budget book puts the same story in the mayor's own words: the process began with a $5.4 million projected shortfall, "the result of slowing new growth revenue, rising fixed costs, and broader pressures on the commercial real estate market" (FY27 budget book). Property taxes supply $291,360,382 of the $394 million FY27 revenue budget — 73.9%. When new growth dries up, there is no other lever of that size. Bean called it a "perfect storm" of declining commercial growth, inflation, health care costs, stagnant state aid and Prop 2½. The city closed the gap with fee increases, roughly 5% cuts to non-personnel budgets, $9 million of reserves used to avoid long-term borrowing, a reorganization, and 13 layoffs — see The FY27 budget. Standard & Poor's reaffirmed the AAA rating anyway, with reserves at about 36% of revenues against a 30% target.

The shift to residential bills

On November 25, 2025 the Council set FY26 rates on Golden's two motions: the minimum residential factor of 82.816 — the legal floor, i.e. the maximum lawful shift of the burden onto commercial property — and a 35% residential exemption for owner-occupied homes, worth $4,582.40, the twelfth consecutive year of it. The rates came out at $18.95 per thousand commercial and $10.99 residential. Golden told the Council the city was seeing "loss of new growth because of the lack of interest in life science buildings," with values falling on both commercial and residential property, and five major life science buildings sitting at roughly 60% completion (Nov 25, 2025 Council). The Council also spent $2.4 million of parking meter receipts to hold the rate down.

The practical effect is arithmetic: the residential factor is already at its legal minimum, so there is no more shift available. As commercial values fall and no new commercial value comes on line, the commercial share of the levy shrinks and the residential share grows — regardless of what the Council votes. That is why the classification hearing each November is the moment this thread becomes visible to residents, and why the FY27 vote, due this November, is the one to cover.

The one variable

TransMedics is the swing factor. Its lease of the nearly 500,000 sq ft building at 188 Assembly Park Drive is, by the city's account, 25% of Somerville's vacant lab space taken off the market in one deal (city announcement, January 13). But the city gave an $18 million TIF to get it, the revenue phases in over ten years starting in year three, and the near-term benefit is an estimated $1.8 million in building permit revenue. Operations aren't due to begin until January 2028. Details on Assembly Square.

Everything else in the pipeline is contingent. 50 Webster Avenue in Union Square is permitted and shovel-ready and waiting on the leasing market. A 19-story lab building at 120 Middlesex Avenue went to the Planning Board on August 6 for site plan approval — new speculative lab space in a market with 1.9 million vacant square feet. And the UCH-TIF zone proposed for Assembly Square and East Somerville is the administration's attempt to convert the problem into housing production: staff told the Land Use Committee the zone is 85% commercial with 59% of commercial leasable square footage vacant or untenanted.

The same numbers cut both ways politically. When the Hamilton Company tried to rezone a Union Square block out of commercial use in April, opponents argued Somerville's commercial tax base — 18.8% — is already dangerously low and that trading commercial land for housing makes this exact problem worse (April 16 Land Use). The city's answer, in effect, is that empty commercial land generates nothing at all.

FY28 is already spoken for

The FY27 budget closed a $5.4 million gap with reserves, 13 layoffs and a 5 percent non-personnel cut, and Bean warned the Finance Committee in June of a "perfect storm" for the year after, flagging that a new elementary school could cost the city $200 million or more (June 9 Finance). FY28 carries roughly $446,000 a year in recurring body-camera costs, which this year came out of a contingency fund; the six school positions the School Committee wanted and the mayor left out; and new growth still projected flat. Wilson has said he will not raise taxes ahead of the November 2027 debt-exclusion vote for the new school at 115 Sycamore Street: "There's no Plan B on that one. We couldn't risk voter fatigue."

What's next

November 2026 — FY27 tax classification hearing and rate vote. The FY26 vote was November 25, 2025; expect the same shape (residential factor plus residential exemption) and watch the commercial-versus-residential value split behind it.
November 3, 2026 — Question 8 would end recreational marijuana sales statewide in 2028; Cambridge Day reports that Cambridge and Somerville together collected about $765,000 in local cannabis taxes in fiscal 2025, revenue the ballot could take off the table just as the lab shortfall bites.
Davis Square — the glut shows up in storefronts, not just towers: Asana's 120,000 sq ft, lab-focused 7th Spoke redevelopment around 260 Elm Street has been frozen since its tenants were cleared out in 2022, and the city is filling the empty Starbucks with a pop-up gallery under a short-term lease (Cambridge Somerville Independent, Sept 14). See Davis Square: the plan and the tower that didn't happen.
January 2028 — TransMedics operations begin; its revenue phases in over ten years starting in year three, so it does not rescue FY27 or FY28.
Ongoing — abatement settlements on the half-built lab buildings, and any distressed sale of a vacant lab building. Bisnow's sources expect maturing construction loans to force sales; a building trading at a steep discount would reset its assessed value downward, cutting the levy further before cheaper rents attract tenants.