26 USC 6013: Rules for Filing Joint Tax Returns

A joint tax return allows a married couple to file a single income tax return, combining their incomes and deductions. This approach often results in a lower tax liability compared to filing separately. The process is governed by 26 U.S. Code § 6013, which outlines who is eligible and the legal implications of doing so. Filing jointly creates a legal obligation for both spouses regarding the accuracy of the return and the payment of any tax due, a concept known as joint and several liability. The regulations also specify how to handle special situations, such as the death of a spouse or a change in filing status.

Eligibility to File a Joint Return

To file a joint tax return, a couple must meet several requirements. The primary condition is marital status; the couple must be legally married as of the last day of the tax year, which is December 31 for most people. This rule applies even if the couple married on that final day. The determination of marriage is based on state law, which may include common-law marriages if recognized by that state.

Couples who are living apart or are separated under an interlocutory, or non-final, decree of divorce are still considered married for tax purposes and can file a joint return. However, once a final decree of divorce or separate maintenance is issued, the individuals are no longer considered married and lose the ability to file jointly for that tax year.

Another requirement is that both spouses must have the same tax year, which for most individuals is the calendar year. A joint return is not permitted if the spouses have different accounting periods. Finally, a joint return cannot be filed if either spouse was a nonresident alien at any time during the tax year, though an exception exists if a specific election is made.

The Concept of Joint and Several Liability

When a married couple files a joint tax return, they agree to “joint and several liability.” This means each spouse is legally responsible for the entire tax liability, including any tax, penalties, and interest from that return. This holds true regardless of which spouse earned the income or claimed the deductions that led to the tax debt.

The Internal Revenue Service (IRS) can collect the full amount of the tax debt from either spouse individually. For example, if one spouse operates a small business and fails to report all of its income on the joint return, the other spouse can be held 100% responsible for the resulting unpaid taxes.

This principle remains in effect even if a divorce decree states that one spouse is responsible for past tax debts. While such a decree may be binding between the former spouses, it does not bind the IRS.

The law does provide for potential relief from this liability. Provisions such as Innocent Spouse Relief, under IRC § 6015, can absolve a spouse from tax debts caused by the other spouse’s errors if specific conditions are met.

Special Circumstances for Joint Filing

Death of a Spouse

The death of a spouse during the tax year does not automatically prevent the filing of a joint return. The surviving spouse can file a joint return for the year of death, covering their own income for the entire year and the deceased spouse’s income up to the date of death. This allows the couple to retain the benefits of the joint filing status for that final year.

A joint return cannot be filed if the surviving spouse remarries before the end of the tax year in which their first spouse died. In that case, the surviving spouse would file a joint return with their new spouse, and a separate return would be filed for the deceased spouse.

The responsibility for signing the return depends on whether a personal representative for the deceased’s estate has been appointed. If an executor is appointed before the return is filed, that representative must sign the joint return along with the surviving spouse. If no representative has been appointed by the filing deadline, the surviving spouse may sign the joint return alone. An appointed executor later has the right to disaffirm the joint return by filing a separate return for the decedent within one year of the original due date.

Nonresident Alien Spouse

A special election permits a U.S. citizen or resident married to a nonresident alien to treat the nonresident spouse as a U.S. resident for all income tax purposes. This election allows the couple to file a joint return and benefit from the corresponding tax rates and deductions. The election is made by attaching a signed statement to the first joint return it applies to.

Making this election has a binding consequence: the couple must agree to report and pay U.S. tax on their combined worldwide income for the entire year. This means all income earned by the nonresident alien spouse from sources outside the U.S., which would otherwise not be subject to U.S. tax, must be included.

Once made, the election remains in effect for all future tax years unless it is terminated or revoked. Termination can occur through the death of either spouse, a legal separation, or revocation by the taxpayers. If the election is terminated, neither spouse can make the election again in any future tax year.

Changing from a Separate to a Joint Return

Taxpayers have the option to change their filing status from married filing separately to married filing jointly after they have already filed their returns. This change is made by filing an amended return using Form 1040-X, Amended U.S. Individual Income Tax Return.

There is a specific time limit for making this change. A couple can amend their returns to file jointly within three years from the original due date of the separate returns, not including any extensions. For example, if separate returns for the 2023 tax year were due on April 15, 2024, the couple would have until April 15, 2027, to file a Form 1040-X.

The reverse, however, is not permitted. Once a couple files a joint return and the tax filing deadline has passed, they cannot choose to amend their return to file as married filing separately for that year. Both spouses must sign the amended return for it to be valid.