Moving from Montreal to Boston: Taxes, Biotech, and the TP-1

Montreal to Boston runs on two pipelines, not one generic Quebec-to-US move. Montreal’s pharma sector, built on decades of Merck, Pfizer, and Bristol Myers Squibb research presence, feeds directly into Cambridge and Boston’s biotech cluster around Kendall Square and the Seaport. Alongside that, McGill and Montreal’s other universities send faculty, postdocs, and research scientists into Harvard, MIT, BU, and Northeastern. This isn’t Montreal to New York’s finance and gaming corridor; it’s a research and lab-bench corridor, and the tax picture underneath it is its own thing.

Why does this specific corridor exist?

Two pipelines drive it, both research-heavy rather than finance-heavy. Pharma and biotech: Montreal’s decades-long presence for Merck, Pfizer, and Bristol Myers Squibb trained a generation of scientists, and Kendall Square in Cambridge, plus the Seaport’s Innovation District, absorbs that talent at scale. Academia: McGill, Université de Montréal, and Concordia feed Harvard, MIT, Boston University, and Northeastern with faculty, postdocs, and research staff moving for a lab or a tenure-track line rather than a salary jump.

Both lanes bring a workforce used to operating in English day to day even in a majority-French city, so this reads as a research-culture move more than a cost-of-living one.

How far does the tax rate actually drop?

Substantially, but not to zero. Quebec’s combined federal-plus-provincial top marginal rate lands around 53.31%, the steepest of any province. Massachusetts taxes most income at a flat 5%, with a 4% surtax on income above roughly $1.08 million, producing a 9% top marginal rate only above that threshold. On a $200,000 salary, the difference is stark: Massachusetts’ flat 5% produces about $10,000 in state tax, versus a Quebec provincial bill several multiples higher on the same income. The drop is real. It just isn’t the disappearing act a move to Florida or Texas would be.

	Montreal / Quebec	Massachusetts
Combined top marginal rate	~53.31%	9% (5% flat, +4% above ~$1.08M)
City/local income tax	None (provincial only)	None anywhere in the state
Sales tax	QST 9.975% + GST 5%, ~14.975% combined	6.25% flat, no local add-on
Separate tax authority	Yes, Revenu Québec	No, runs through the Massachusetts DOR
Rate structure	Graduated, tops at 25.75% at ~$126,000	Flat, with a surtax cliff at ~$1.08M

Which three tax authorities apply in the move year?

The CRA, Revenu Québec, and the IRS, and that’s before Massachusetts is even in the picture. The final TP-1 goes to Revenu Québec, covering worldwide income to the departure date and Quebec-source income after. The final T1 goes to the CRA, covering the same period federally. The IRS then gets a US return, dual-status or full-year under the first-year election, and Massachusetts rides on top of that as a part-year state return. Four filings from one move, and none of them are optional even if the amounts on each are small.

What replaces my T4 and T5 on the way out?

Relevé slips. Quebec issues its own slips for the provincial return, the Relevé 1 for employment income alongside the federal T4, and the Relevé 3 for investment income alongside the T5. A partial-year Montreal employer, common for anyone leaving mid-grant-cycle at a pharma employer, issues the Relevé 1 on its own timeline, often weeks after the T4. The TP-1 can’t be finished from a T4 total alone, and the Quebec abatement, a 16.5% reduction of basic federal tax, has to be prorated to the months of actual Quebec residency in a departure year.

What happens to RAMQ, RRQ, and my RRSP?

RAMQ coverage doesn’t end automatically when you leave, so notify the Régie de l’assurance maladie du Québec directly once the departure date is set; that notice runs separately from anything filed with Revenu Québec or the CRA. RRQ, Quebec’s version of CPP, keeps paying on its existing schedule after the move, and the treaty treats it exactly like CPP for a US resident: taxable only in the US once you’re a US tax resident.

The RRSP carries over the same way it would for any departing Canadian, and Massachusetts follows the federal treaty treatment under Article XVIII, with no state-level addback of untaxed RRSP growth.

How steep is Quebec’s departure tax before Massachusetts?

Quebec’s provincial bracket tops out at 25.75% on income over roughly $126,000, and it applies to the Quebec-source portion of any deemed-disposition gain under ITA 128.1(4) the same way it applies to ordinary income. The federal deemed disposition mechanics don’t change by province, but the rate the gain is taxed at provincially is higher leaving Quebec than anywhere else in Canada. The departure tax forms guide covers the T1161 and T1243 filings, which apply here without modification.

What about the millionaire’s surtax and equity comp?

Biotech moves often carry equity, options, or a liquidity event tied to a licensing deal or an exit, and that’s exactly where the surtax matters. Massachusetts’ 4% surtax applies to every dollar of income above roughly $1.08 million in a given year, not just the excess in a graduated sense, it’s a flat additional rate stacked on the 5% base for everything over the line. A large vesting event or a bonus tied to a drug approval milestone can push a otherwise-ordinary year over the threshold, and timing that recognition around both the surtax line and the Canadian departure date is a real planning conversation.

What changes on everyday cost of living?

Sales tax drops meaningfully. Quebec’s combined QST and GST run about 14.975% on most purchases. Massachusetts charges a flat 6.25% with no local add-on anywhere in the state, and groceries and most clothing are exempt. Property tax tells a different story: Boston itself runs roughly 1.0% to 1.2% on residential property, kept moderate by a large commercial tax base, while Cambridge runs similarly. That’s not dramatically different from many Montreal boroughs on the rate, but Boston-area home values are considerably higher, so the dollar amount often lands well above what the same rate produced in Montreal.

• Biotech and pharma arrivals cluster around Cambridge and Kendall Square, walkable to the lab campuses, or the Seaport’s Innovation District closer to the newer biotech towers
• Academic arrivals lean toward Cambridge near Harvard and MIT, or Somerville for junior faculty and postdocs on a tighter budget
• Families further along in a career tend to land in Brookline or Newton, a longer commute but with the school districts driving the decision
• None of this changes the state tax picture; Massachusetts taxes residents the same flat 5% regardless of town, but neighborhood choice does drive the property tax dollar amount above

What about estate tax if I settle permanently?

Massachusetts has a state estate tax with an exemption of only $2 million, well below the federal exemption of $13.61 million, and it carries a cliff effect: once the gross estate exceeds $2 million, the tax applies to the entire estate, not just the amount above the threshold. Rates run from 0.8% to 16%. This threshold catches a Massachusetts domiciliary faster than most people expect, particularly once a Cambridge-area home and retirement accounts are added together. Quebec has no separate estate or inheritance tax, so this is a new concept, not just a lower number.

What should I do next?

Close the Quebec side first. Confirm the departure date, gather both the T4/T1 and Relevé/TP-1 slip sets, notify RAMQ directly, deregister for QST if applicable, and prorate the Quebec abatement to the months of actual residency. Then build the Massachusetts side: confirm state residency once the lease is signed, and decide between a dual-status and full-year US election before filing anything with the IRS.

• Moving from Canada to Massachusetts, the province-level version of this corridor
• Moving from Quebec to the US, the full Quebec departure mechanics
• Moving from Montreal to New York, the finance and gaming corridor from the same city
• Moving from Montreal to Miami, the no-state-income-tax comparison from Quebec
• Moving from Quebec to Florida, the other no-income-tax comparison
• The Canadian departure tax and its forms
• The leaving-Canada checklist
• RRSP and TFSA moving to the US
• The US-Canada tax treaty explained
• Your first US tax return as a new immigrant
• Provincial health insurance and leaving Canada, the RAMQ notice mechanics
• State income tax and the treaty, why Massachusetts isn’t bound by the federal treaty the way the IRS is
• Toronto to Boston, the two-authority version from Ontario
• Montreal to Chicago, the flat-tax Midwest corridor from Quebec
• Montreal to Los Angeles, the VFX and entertainment corridor
• Montreal to San Francisco, the AI and deep learning corridor
• Montreal to Washington DC, the international organizations corridor
• Montreal to Austin, the AI and tech corridor into Texas

This guide is general information, not tax advice for your specific situation. Which points apply, and how, depends on your facts.