Documents Needed for Connecticut Estate Tax Filing

If you've recently lost a loved one and you're now responsible for settling their estate in Connecticut, the paperwork can feel overwhelming. Knowing exactly what documents are required for Connecticut estate tax filing is one of the first things you need to figure out and getting it wrong can lead to delays, penalties, or unnecessary stress during an already difficult time. This article walks you through every document you'll need, why each one matters, and how to avoid the mistakes that trip people up.

What exactly does Connecticut estate tax filing require?

Connecticut is one of the few states that imposes its own estate tax, separate from the federal estate tax. The state requires an estate tax return for any resident whose gross estate exceeds the applicable exemption threshold. As of recent years, that exemption has been set at $9.1 million (indexed for inflation), but it's always smart to confirm the current exemption with the Connecticut Department of Revenue Services.

Filing isn't just about filling out a form. You need to compile a thorough package of financial records, legal documents, and supporting evidence that proves the value of everything the deceased person owned. The state uses these documents to verify the estate's total value and determine whether any tax is owed.

Understanding the CT-706 form instructions is a good starting point, but the form itself only tells part of the story. The documents you attach and submit alongside it are what make or break your filing.

Which financial records do I need to gather first?

Start with the documents that establish the value of the deceased person's financial assets. These are the core records Connecticut expects to see:

Bank statements Savings, checking, money market, and CD accounts. You'll need statements dated as close to the date of death as possible.
Investment account statements Brokerage accounts, mutual funds, stocks, bonds, and any other securities holdings, also valued at the date of death.
Retirement account records IRA, 401(k), 403(b), and pension documents. If the estate includes an IRA, the required forms for estate settlement with an IRA will outline additional documentation you may need.
Life insurance policies Copies of all policies, including the face value and any riders. Note whether the deceased owned the policy, since that affects whether it's included in the gross estate.
Outstanding debts and liabilities Mortgage statements, credit card balances, personal loans, medical bills, and any other obligations owed at the time of death.

These financial records form the backbone of the estate's valuation. Without them, you can't accurately complete the asset schedules on the CT-706.

What property and asset documents should I prepare?

Beyond financial accounts, Connecticut requires documentation for real property and other tangible assets. Here's what to collect:

Real estate deeds and titles For any property the deceased owned in Connecticut or elsewhere. You'll need the legal description, current market value, and any outstanding mortgage information.
Recent appraisals The state may require independent appraisals for real property, valuable personal property (jewelry, art, collectibles), and business interests. These should be dated close to the date of death.
Vehicle titles and registrations Cars, boats, RVs, and other titled vehicles.
Business ownership documents If the deceased owned a business, partnership interest, or LLC membership, you'll need operating agreements, buy-sell agreements, and recent financial statements for the business.
Personal property inventory A detailed list of household items, furnishings, and other tangible personal property with estimated values.

Accurate valuations matter here. Overstating or understating asset values can raise red flags with the Connecticut Department of Revenue Services.

Do I need a death certificate and the original will?

Yes. These are non-negotiable documents for Connecticut estate tax filing:

Certified death certificate You'll need multiple certified copies. Most agencies and financial institutions won't accept photocopies. Order at least 10–15 copies from the Connecticut vital records office or the funeral home.
Last will and testament The original, if available. This must be filed with the probate court in the district where the deceased lived. The will names the executor (also called the fiduciary in Connecticut), who is typically the person responsible for filing the estate tax return.
Trust documents If the deceased had a revocable living trust or any irrevocable trusts, gather the full trust agreements. Trust assets may be included in the gross estate depending on the trust terms.

The probate court and the estate tax filing work in tandem. If you're unfamiliar with how the two processes connect, reviewing the steps for filing a Connecticut estate tax return after death can help clarify the timeline.

Which forms must I submit with the estate tax return?

The Connecticut estate tax filing package typically includes more than just the main return. Here's what you'll need to prepare and submit:

Form CT-706 The Connecticut Estate and Gift Tax Return. This is the primary form, and every required estate must file it.
Form CT-706 NT The Estate Tax Return for Non-Trust Estates, if applicable.
Federal Form 706 A copy of the federal estate tax return, if one was filed with the IRS. Even if the estate isn't large enough to owe federal tax, Connecticut may still require a copy.
Federal estate tax closing letter If the IRS has completed its review, include this as supporting documentation.
Any prior Connecticut gift tax returns If the deceased made taxable gifts during their lifetime, copies of those filings are needed because Connecticut has a gift tax that interacts with the estate tax.

Filing the wrong form or leaving one out is a common reason for processing delays. Double-check that you have the correct versions of each form for the tax year in question.

What if the estate includes jointly held property or gifts?

Jointly owned property and lifetime gifts each have their own documentation requirements:

Joint tenancy or tenancy by the entirety documents For real estate or financial accounts held jointly with a spouse or other person, you'll need proof of ownership structure. Depending on how the property was held, only a portion of the value may be included in the gross estate.
Gift tax returns (federal Form 709) If the deceased made gifts exceeding the annual exclusion amount during their lifetime, those returns must be gathered. Connecticut's estate tax calculation includes adjusted taxable gifts.
Gift records and documentation Even for gifts that didn't require a federal return, having records of significant transfers helps ensure accuracy.

What documents do I need if there are deductions or credits to claim?

Connecticut allows certain deductions that reduce the taxable estate. Supporting documents for these deductions include:

Funeral expense receipts Itemized bills from the funeral home and related service providers.
Administrative expense records Attorney fees, executor fees, accounting fees, and costs associated with maintaining estate property.
Charitable donation documentation If the estate made bequests to qualified charities, you'll need copies of the relevant will provisions or trust terms and confirmation letters from the charitable organizations.
Marital deduction documentation If assets pass to a surviving spouse, gather proof of the transfer and the marriage certificate.
Credit for state estate taxes paid to other states If the deceased owned property in another state that also imposes an estate tax, include proof of those tax payments.

What are the most common mistakes people make with these documents?

When filing an estate tax return, small errors in documentation can cause big problems:

Using outdated valuations Asset values must reflect the date of death, not a prior appraisal date. Stale appraisals will be questioned.
Forgetting about digital assets Cryptocurrency, online payment accounts, and digital investment platforms count as reportable assets. Include statements for these.
Missing the filing deadline Connecticut's estate tax return is due within six months of the date of death. If you're unsure about timing, check the specific due date rules for Connecticut estate tax returns.
Not reporting all gifts Lifetime gifts made by the deceased are added back into the taxable estate. People often overlook gifts made in the years before death.
Submitting incomplete schedules Each asset category on the CT-706 has its own schedule. Leaving a schedule blank when there are assets to report will trigger a notice from the state.

How should I organize everything before filing?

A messy document package slows down the review process. Here are practical ways to stay organized:

Create a master spreadsheet listing every asset, its value, and the source document you're using to support that value.
Group documents by category: financial accounts, real property, personal property, debts, tax forms, and legal documents.
Keep originals in a secure location and submit copies to the state unless originals are specifically requested.
Work with a Connecticut estate attorney or CPA who handles estate tax filings they know what the state expects and can catch gaps before you submit.

Practical checklist for Connecticut estate tax filing documents

Use this checklist to make sure you have everything before you sit down to file:

Certified death certificate (multiple copies)
Original will and any trust agreements
Bank and financial account statements (date-of-death values)
Investment and brokerage account statements
Retirement account documents (IRA, 401(k), pensions)
Life insurance policy copies and ownership information
Real estate deeds, titles, and recent appraisals
Vehicle titles and registrations
Business ownership documents and valuations
Personal property inventory with estimated values
Outstanding debt records (mortgages, loans, credit cards, medical bills)
Funeral expense receipts
Administrative expense documentation
Charitable bequest records
Marriage certificate (if claiming marital deduction)
Federal Form 706 (if filed)
Federal estate tax closing letter (if available)
Federal gift tax returns (Form 709)
Connecticut gift tax returns (if any)
Completed Form CT-706 and all applicable schedules

Tip: Start gathering these documents as soon as possible after the date of death. Financial institutions can take weeks to provide statements, and appraisals take time to schedule. Don't wait until the filing deadline is approaching to begin the six-month window goes faster than most people expect.