Updated September 4, 2026. Quick answer: Connecticut taxes estates above $15,000,000 in 2026 at a flat 12% on the excess, with total Connecticut gift and estate tax capped at $15,000,000 in aggregate. Unlike federal law, Connecticut gives filers only six months, not nine, to file Form CT-706/709, and the state exemption does not carry portability between spouses.
2026 exemption: $15,000,000 · Top rate: 12% flat on the excess over the exemption · Key statute: Conn. Gen. Stat. sec. 12-391(g)
Filing deadline: six months, not the federal nine
Connecticut’s estate and gift tax return, Form CT-706/709, is due sooner than its federal counterpart. The Connecticut DRS states the form must be filed no later than six months after the decedent’s date of death unless an extension of time to file is requested, compared to the federal Form 706’s nine-month deadline. An extension request is filed on Form CT-706/709 EXT, and a separate extension of time to pay of up to six months is available if the fiduciary shows reasonable cause.
No state-level portability of the Connecticut exemption
Connecticut’s $15,000,000 exemption tracks the federal basic exclusion amount in size, but Conn. Gen. Stat. 12-391 contains no mechanism letting a surviving spouse inherit a deceased spouse’s unused Connecticut exemption. The statute defines the federal basic exclusion amount only as the IRS-published filing threshold and builds the Connecticut rate schedule off that single number, with no DSUE or portability election language anywhere in the section. Exemption unused at the first spouse’s death is lost at the Connecticut level even where federal portability would preserve it federally, so trust-based planning to use both spouses’ exemptions still matters for Connecticut residents.
How the $15 million cap works: a ceiling on tax paid, not on estate value
Above the exemption, Connecticut taxes the excess at a flat 12%. Separately, the statute caps the total dollars of tax owed: in no event shall the amount of tax payable under this section exceed fifteen million dollars for deaths on or after January 1, 2019, up from a $20,000,000 cap that applied to deaths between 2016 and 2019. Because the cap limits aggregate tax dollars, combined lifetime Connecticut gift tax and estate tax, rather than estate value, it only binds on very large estates, arithmetically around $140,000,000 and up at the 2026 rate.
Six months to file, and no unused exemption to fall back on.
Connecticut taxes the excess over $15,000,000 at a flat 12%, but it gives an estate three months less than the federal return does, and an exemption left unused at the first death does not pass to the surviving spouse. Both of those are planning problems with a date attached to them.
Before you start, what actually happens. The form is run by Kapitalwise, our advisor-matching partner. Kapitalwise sends your details to advisers who pay for the introduction, so expect calls and texts. Clear Money Guide is paid when you submit the form, whether or not you ever hire anyone. This is free to you and there is no obligation to hire anyone.
The Kapitalwise form opens here, and you stay on this page.
What happens when you press the button
It asks about nine questions (age, investable assets, location), then your name, email and phone number, and verifies the phone by text. Nothing loads and nothing reaches Kapitalwise until you press the button.
Nonresident decedents: Connecticut taxes only Connecticut-situs property, by apportionment
Connecticut estate tax reaches nonresident decedents who own Connecticut real estate or tangible personal property physically located in the state. Property of a nonresident estate over which Connecticut has jurisdiction for estate tax purposes includes real property situated in the state and tangible personal property having an actual situs in the state. The tax is computed on the full estate under the resident schedule, then apportioned by a fraction whose numerator is the value of the part of the decedent's gross estate over which Connecticut has jurisdiction and whose denominator is the value of the decedent's gross estate, so a nonresident's bill scales with the Connecticut-situs share of their total wealth.
The math on a $16,000,000 estate
Tax owed: $120,000. $16,000,000 taxable estate minus the $15,000,000 exemption equals $1,000,000 of excess. $1,000,000 times the flat 12% rate equals $120,000 in Connecticut estate tax. The $15,000,000 aggregate tax cap does not affect this result; the cap would only start to bind on an estate near $140,000,000.
Honest gaps
cga.ct.gov, the Connecticut General Assembly's own statute site, was unreachable this session, so the statute text was verified through its FindLaw reproduction. No DRS or statutory source was found stating in so many words that portability is unavailable; that conclusion is drawn from the complete absence of any DSUE or spousal-portability provision in the full text of Conn. Gen. Stat. 12-391.
Source note. Read from https://portal.ct.gov/drs/individuals/individual-income-tax-portal/estate-and-gift-taxes/tax-information; https://codes.findlaw.com/ct/title-12-taxation/ct-gen-st-sect-12-391/ on 2026-09-04.
Related: estate tax by state · who actually pays the estate tax · the lifetime gift and estate tax exemption.
Statutory text read at each state's own department of revenue or legislature. General information, not legal or tax advice; exemptions, rates and filing rules change, and a qualified estate or tax professional should confirm the current figures before you rely on them.