What the rule says
Connecticut's estate tax framework, codified at Conn. Gen. Stat. § 12-391, has a unique combination of features that distinguish it from every other state estate tax:
Federal-conformed exclusion
Connecticut's estate tax exclusion conforms to the federal exclusion (~$13.99 million per individual in 2026, indexed annually). This is the highest state estate tax threshold in the country — equal to the federal threshold.
Connecticut achieved federal conformance through a series of legislative changes that gradually raised the state threshold to match the federal exclusion. As of 2023 and continuing forward, Connecticut's threshold is set at the federal exclusion amount.
Portability
Connecticut recognizes federal portability of unused exclusion between spouses. This is unique among state estate taxes — Massachusetts, Illinois, Minnesota, Oregon, New York, and other state estate taxes do not recognize portability. Connecticut alone does.
The portability recognition means a Connecticut married couple can effectively double the state exclusion to ~$27.98 million through standard federal portability election.
Tax rates
Connecticut's top estate tax rate is 12% — lower than most other state estate taxes (Massachusetts top rate 16%, NY top rate 16%, etc.).
What this means in practice
Connecticut's framework produces significantly different planning outcomes than other estate-tax states:
Most CT estates face no state estate tax
With the threshold conformed to the federal $13.99M, most Connecticut estates that would face Massachusetts ($2M), Minnesota ($3M), or Illinois ($4M) state estate tax face NO Connecticut estate tax.
Married couples can use portability
Unlike Massachusetts (where a couple must use bypass trust planning to capture the deceased spouse's $2M exclusion), Connecticut couples can elect federal portability and effectively double the state exclusion to ~$27.98M.
Lower top rate reduces tax for very large estates
For Connecticut estates above the federal threshold, the 12% top rate is meaningfully lower than other states' 16% top rates.
How CT compares to other estate-tax states
Connecticut's framework is in a unique category:
- CT: $13.99M (federal-conformed) with portability — only state with both features - NY: $7.16M no portability with cliff effect - IL: $4M no portability - MN: $3M no portability - MA: $2M no portability - OR: $1M no portability
Connecticut's framework reflects a deliberate policy choice. Connecticut historically had a higher state estate tax burden but has progressively reduced it through the federal conformance and portability provisions.
Federal interaction
Connecticut estate tax operates alongside federal estate tax with substantial alignment:
- Estates below $13.99M (2026): No federal AND no Connecticut estate tax. - Estates between $13.99M (single) and $27.98M (married with portability): Federal estate tax applies; Connecticut estate tax may also apply on the state-level overlay portion (depending on specific calculations). - Estates above $27.98M: Both federal and Connecticut tax apply.
What you can do about it
For Connecticut residents:
- Most CT estates need no state estate tax planning. With the threshold at federal levels, most estates pass without state tax. - High-net-worth CT residents focus on federal planning. Connecticut's framework follows federal closely. - File Form 706 for portability. Critical for both federal and Connecticut purposes. - Coordinate with overall planning. Connecticut residents need not engage in bypass trust planning for state estate tax purposes (different from MA, MN, IL, OR). - Engage a Connecticut estate tax advisor for very large estates. $13.99M+ estates need careful planning.
For non-Connecticut residents considering relocation:
- Connecticut's framework is favorable for high-net-worth residents compared to MA, NY, NJ, but not as favorable as no-state-tax states (FL, TX, NH, etc.).
Sunset considerations
The federal estate tax exclusion is scheduled to sunset to ~$7M (indexed) on January 1, 2026, unless Congress acts. Connecticut's federal-conformed framework would mirror that sunset — Connecticut threshold would drop to ~$7M as well. This is a substantial consideration for high-net-worth Connecticut residents whose estate planning depends on the current $13.99M threshold.
Legislative monitoring is essential. Sunset provisions could substantially change Connecticut estate tax exposure for affected estates.
Who this affects most
Connecticut's estate tax framework is most consequential for:
- High-net-worth Connecticut residents whose estates approach the federal/state exclusion - Connecticut residents who have heard about other states' estate taxes and incorrectly assume Connecticut's is similarly aggressive - Estate planners coordinating CT-specific exposure with federal planning (which is largely the same) - Families considering Connecticut residency for tax efficiency relative to MA, NY
Connecticut's unique combination of federal-conformed exclusion and portability makes it the most favorable state estate tax in the country among states that have one. For most Connecticut residents, federal planning controls and state-specific overlays are minimal.