The estate's own tax number, and the order the first year runs in

A death produces a set of federal tax obligations that arrive in a fairly predictable order — but nobody hands anyone the order. This is the shape of it: what exists, roughly when, and which pieces depend on which. It is a map of the federal system rather than a filing plan for any particular estate.

First, the estate acquires an identity

While a person is alive, their Social Security number identifies everything they earn. After death, income the property produces belongs to a different taxpayer — the estate — and the IRS identifies that taxpayer with an employer identification number. The Form 1041 instructions state the requirement without qualification: every estate that is required to file Form 1041 must have one.

The name misleads and is worth defusing early. An employer identification number implies no employees, no payroll and no business. It is the taxpayer identification number for an entity that is not a natural person, and an estate is one of those.

How one is obtained

• The application is Form SS-4. The IRS issues the number immediately through its online application once the information submitted is validated; the same form can be mailed or faxed instead. Applying by telephone is an option available only to international applicants.
• The instructions say to enter the name of the estate on the first line — and, for an estate that has no legal name, the decedent's name followed by the word "Estate."
• On the line asking when the business started or was acquired, the instructions direct estates to enter the date of death of the decedent named on the first line, or the date the estate was legally funded.
• Applications are limited to one number per responsible party per day. For a decedent's estate, the instructions say that limitation is applied to the decedent.

Then the returns, in the order the dates dictate

• Any return the person never filed for an earlier year. Where someone dies after a tax year has closed but before filing for it, that return is an ordinary full-year return and remains due on its own deadline.
• The final Form 1040. It covers the first day of the year of death through the date of death, and it is due when the person's return would have been due had they lived — for a calendar-year taxpayer, the ordinary spring deadline of the following year.
• A federal estate tax return, Form 706, but only if one is required at all. That turns on whether the gross estate plus adjusted taxable gifts exceeds the basic exclusion amount, which is indexed for inflation and stated in the Form 706 instructions for the year of the death. It is due within nine months of the date of death, and Form 4768 requests an automatic six-month extension of time to file.
• The estate's own income tax return, Form 1041, for each year the estate has enough income to require one. Its first tax year begins at the moment of death, and the personal representative chooses when that year ends: any period of twelve months or less finishing on the last day of a month.

Two pieces of room in the first two years

The federal rules leave a decedent's estate some slack in the period when everything else is happening at once. A decedent's estate is not required to make estimated tax payments for any tax year ending before the date that is two years after the death — an exception printed both in the Form 1041 instructions and in the instructions to Form 1041-ES. And the estate's freedom to choose a fiscal year, rather than being locked to the calendar, means its first deadline need not sit on top of the deadline for the final individual return.

The sequencing rule that carries personal liability

There is one place in the first year where the order genuinely matters rather than merely being tidy. Where a decedent's estate is insufficient to pay all the decedent's debts, debts due to the United States are paid first — and both the decedent's federal income tax liabilities at the time of death and the estate's own income tax liability are debts due to the United States.

Beneficiaries are not fully insulated either. Where estate assets are distributed without the taxes due being paid, a beneficiary can be liable for the unpaid tax to the extent of the value of the assets they received. Money that has already been spent is still money they received.

How the job gets closed out

Two forms exist for winding up, and both exist because the exposure above is real. Form 4810 requests a prompt assessment of tax, which shortens the period during which the IRS can charge additional tax after a return has been filed. Form 5495 requests discharge from personal liability for the decedent's income, gift and estate taxes, and can only be made after the returns for those taxes are filed; the IRS then has nine months to notify the executor of the amount due, and paying it discharges personal liability for later deficiencies. Even after discharge, tax can still be assessed against the executor to the extent they are still holding the decedent's property.

What is not on this map

State tax is a separate system and it is not described here. There is state income tax, which is its own return with its own rules and deadlines. And there are the death taxes: a small number of states impose an estate or inheritance tax of their own, on their own terms, entirely independently of whether any federal estate tax return is required. Whether either applies is a question about where the person lived and where the property sits, and it is answered locally.

The federal shape above describes what exists, not what any given estate has to do. The order the returns are filed in, whether a fiscal year helps, when to distribute and when to wait — those decisions carry money and, as the liability rules show, occasionally more than money. They are everyday work for a CPA or an enrolled agent, and the instructions to every form named above are published free on the IRS website for anyone who wants to check an article against its source.