Joint bank accounts and inheritance tax intersect in two very different ways, and most people only hear about one of them. At the federal level, the IRS can pull some or all of a joint account balance into the deceased owner’s estate, but with the 2026 estate tax exemption at $15 million per person, few families will actually owe federal estate tax.1Internal Revenue Service. What’s New – Estate and Gift Tax The tax that catches people off guard is state inheritance tax, which five states still impose on the surviving owner and which applies no matter how small the estate is.
The Federal Default: 100% Goes Into the Estate
The IRS starts from a strict presumption. When one owner of a joint account with right of survivorship dies, the entire balance is treated as belonging to the decedent’s estate.2Office of the Law Revision Counsel. 26 USC 2040 – Joint Interests The surviving owner has the burden of showing otherwise.
The way to rebut that presumption is the contribution test. If you can prove you deposited 40% of the funds from your own earnings or assets, that 40% is excluded from the deceased owner’s estate and the remaining 60% stays in.3eCFR. 26 CFR 20.2040-1 – Joint Interests The IRS cares who actually put the money in, not whose name is on the signature card.
One trap catches many families. Money the surviving owner received as a gift from the deceased person does not count as the survivor’s own contribution. If a parent deposited $200,000 into a joint account, gifted $50,000 of it to the adult child co-owner, and the child redeposited that $50,000 into the same account, the IRS still treats the parent as having funded the whole balance.2Office of the Law Revision Counsel. 26 USC 2040 – Joint Interests Only money traceable to the survivor’s independent income or wealth qualifies.
That tracing requirement demands serious record-keeping. Deposit slips, bank statements, and transfer records going back to when the account was opened. Without them, the IRS defaults to including 100% of the balance in the decedent’s estate, and executors handling a decades-old joint account with no paper trail are stuck with that result.
Spouses Get an Automatic 50/50 Split
Married couples are treated differently. When spouses are the only two owners of a joint account, the IRS automatically includes exactly 50% of the balance in the estate of the first spouse to die, regardless of who actually funded it.2Office of the Law Revision Counsel. 26 USC 2040 – Joint Interests If one spouse contributed everything, the included amount is still half.
That 50% inclusion almost never generates tax. The unlimited marital deduction lets any amount of property pass tax-free from a deceased spouse to a surviving spouse who is a U.S. citizen.4Office of the Law Revision Counsel. 26 USC 2056 – Bequests to Surviving Spouse The executor reports the inclusion on Schedule E of Form 706, claims a matching deduction on Schedule M, and the net tax on the transfer is zero.
If the surviving spouse is not a U.S. citizen, the picture changes. The marital deduction is disallowed, and the automatic 50/50 split under the qualified joint interest rule no longer applies.4Office of the Law Revision Counsel. 26 USC 2056 – Bequests to Surviving Spouse The full consideration-furnished test applies instead, and the non-citizen spouse has to prove their own contributions to exclude any portion of the account.
Parent-Child and Convenience Accounts
For any joint account between people who are not spouses, the full contribution test applies. The most common setup is a parent adding an adult child so the child can help pay bills or manage finances if the parent becomes incapacitated. These convenience arrangements carry real tax exposure.
If the parent funded the entire account and the child was added only for access, 100% of the balance is included in the parent’s gross estate at death.3eCFR. 26 CFR 20.2040-1 – Joint Interests The child’s name on the account does not change that. The IRS looks past the legal title to whoever actually put the money in.
The survivor often does not realize they can be on the hook for a share of any estate taxes owed. The account transfers automatically through survivorship rights, but if the estate lacks other assets to cover its tax bill, the executor can seek contribution from the co-owner who received the account. Getting the funds through survivorship is not the same as getting them tax-free. A Payable-On-Death designation produces the same result at the federal level: the probate shortcut and the tax calculation are separate questions.
State Inheritance Tax Is Where Most People Actually Get Hit
Federal estate tax rarely applies. State inheritance tax is another story. Five states still impose an inheritance tax, and unlike estate tax, an inheritance tax is paid by the person receiving the assets, not by the estate. The rate depends almost entirely on the recipient’s relationship to the deceased owner.
In these states, a surviving spouse who receives a joint account through survivorship typically pays nothing. Children and other direct descendants generally face low rates, often in the range of 0% to about 4.5%. Siblings tend to land in the 10% to 12% range. A joint account passing to an unrelated person or distant relative can be taxed at rates reaching 15% or 16%, depending on the state.
State inheritance tax also ignores the federal contribution test. The state does not care who deposited the money. It cares who received it and how closely they were related to the person who died. If a parent adds an unrelated caregiver to a joint account, the full balance passing to that caregiver can be taxed at the highest inheritance bracket in the parent’s state of residence.
The result is that a joint account can escape federal estate tax entirely because the decedent’s estate is nowhere near the $15 million threshold, yet the surviving co-owner still receives a state inheritance tax bill. The executor must determine the deceased owner’s state of residence at death to know whether a state inheritance or estate tax applies, and the surviving account holder, not the estate, is personally responsible for paying the tax.
When Form 706 Has to Be Filed
For 2026, the federal estate tax exemption is $15 million per person, so a married couple can shelter up to $30 million between them.5Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026 A joint account with $500,000 in it will be included in the gross estate calculation but will almost certainly generate zero federal tax unless the total estate exceeds the exemption.
Estates that do exceed the threshold must file Form 706 and report all jointly owned property on Schedule E. The executor lists the full value of the joint account, then shows the amount excluded based on the survivor’s proven contribution. Schedule E is split into Part I for qualified joint interests between spouses (the automatic 50%) and Part II for all other joint interests, which are governed by the contribution test.6Internal Revenue Service. Instructions for Form 706
Some estates below the exemption still file Form 706 to elect portability, which transfers a deceased spouse’s unused exemption to the survivor. That election requires a complete return, joint accounts included. Skipping the filing because no tax is due can cost the surviving spouse millions in exemption later.
Gift Tax When the Co-Owner Withdraws
Adding someone’s name to your bank account does not itself trigger gift tax. The IRS treats opening a joint account as an incomplete gift because you can still pull all the funds out without the other person’s permission. The taxable event happens later, when the co-owner withdraws money for their own use.7GovInfo. 26 CFR 25.2511-1 – Transfers in General
At that point, the amount withdrawn counts as a gift from whoever deposited the funds. If the co-owner takes out more than $19,000 in a single year, the 2026 annual gift tax exclusion, the depositing owner has to file Form 709.1Internal Revenue Service. What’s New – Estate and Gift Tax Filing does not necessarily mean owing tax, because the excess applies against the lifetime exemption, but not filing can cause problems later.8Internal Revenue Service. Instructions for Form 709
This creates a planning bind. If the non-contributing co-owner pulls out large sums during the original owner’s lifetime, those withdrawals are taxable gifts. If they wait and take the whole balance through survivorship at death, the full amount gets swept into the decedent’s gross estate under the contribution test. Either way, the IRS is involved.
Why Reporting Still Matters When No Tax Is Owed
Even when the estate owes no tax, properly documenting the joint account matters because it sets the surviving owner’s basis in the inherited portion. Property included in a decedent’s gross estate gets a stepped-up basis equal to its fair market value at the date of death.9Office of the Law Revision Counsel. 26 USC 1014 – Basis of Property Acquired From a Decedent
For a spousal account, the surviving spouse gets stepped-up basis on the 50% included in the deceased spouse’s estate; the other half keeps its original basis. For a non-spousal account, the step-up applies to whatever percentage was included. If the deceased owner funded 100%, the survivor gets a full basis step-up on the entire amount.
With plain cash, the step-up has limited practical impact. But joint accounts holding certificates of deposit bought at a discount, or funds that will be reinvested after transfer, benefit from accurate basis tracking. Reporting also creates a clean paper trail if the IRS later questions the survivor’s cost basis on anything purchased with the inherited money.