A sibling can open a bank account for a minor, but the account belongs to the minor, not the sibling

Yes, a sibling can open a bank account on behalf of a minor. However, the account is legally the minor's account, and the sibling acts as a custodian or co-owner depending on how the bank structures it. The minor's parent or legal guardian must typically be involved—either as the primary account holder with the sibling as a secondary contact, or the sibling must have documented legal authority to act on the minor's behalf.

Banks have different rules about who can open an account for someone under 18. Some require a parent or guardian to be present or to sign documents. Others allow a sibling to open the account if they can prove they have custody or guardianship of the minor. A few banks have no age minimum and let any adult open a custodial account, but this is less common.

The key distinction is custodial versus joint ownership. In a custodial account, the sibling holds the money in trust for the minor until they reach the age of majority (usually 18 or 21, depending on state law). In a joint account, both the sibling and minor have equal legal rights to the money. Most banks default to custodial accounts when a minor is involved, which protects the minor's money from the sibling's creditors.

Key Takeaways

  • A sibling can open a custodial account for a minor, but the account legally belongs to the minor, not the sibling.
  • Most banks require proof that the sibling has legal authority to act for the minor—either as a guardian, or with written permission from the parent or legal guardian.
  • Custodial accounts transfer to the minor's full control at age 18 or 21, depending on state law and the account type.
  • The sibling's access to the account ends when the minor reaches the age of majority, even if the sibling set up the account.

What banks actually ask for when a sibling opens an account

When you walk into a bank or call to open an account for a minor, the bank will ask for identification and proof of the minor's identity. You will need the minor's Social Security number or Individual Taxpayer Identification Number (ITIN). Most banks also ask for the minor's birth certificate or a copy of it.

The critical question is whether you are the parent, guardian, or someone else. If you are a sibling without legal guardianship, the bank will usually ask for written consent from the parent or legal guardian. Some banks require the parent or guardian to be present in person. Others accept a notarized letter or a copy of custody documents.

If you are the legal guardian of the minor (which is different from being a sibling), you will need to bring documentation of that guardianship—a court order, custody agreement, or adoption papers. Banks treat guardians the same way they treat parents for account purposes.

Custodial accounts and what happens when the minor turns 18

Most accounts opened for minors are custodial accounts under the Uniform Transfers to Minors Act (UTMA) or the Uniform Gifts to Minors Act (UGMA). These are state laws that govern how money held in trust for a minor is managed and transferred. The sibling acts as the custodian, meaning they can deposit money, withdraw funds for the minor's benefit, and manage the account—but the money is not theirs.

When the minor reaches the age of majority, the custodial account automatically converts to a regular account in the minor's name alone. The sibling's authority ends. The minor can then do whatever they want with the money, including withdraw it all. Some states set the age of majority at 18; others use 21. Check your state's law or ask the bank which age applies to the account you are opening.

The sibling cannot keep the money or prevent the minor from accessing it once they reach the age of majority. This is a legal protection built into custodial accounts. If the sibling has concerns about how the minor will use the money, that is a family conversation to have before opening the account, not something the account structure can enforce.

The difference between a custodial account and a joint account

A custodial account is held in the minor's name, with the sibling listed as custodian. The money belongs to the minor from day one. The sibling can manage it but cannot claim it as their own for tax purposes or in a bankruptcy. When the minor turns 18 or 21, the account becomes theirs entirely and the sibling has no further rights.

A joint account lists both the sibling and the minor as owners. Both have equal legal rights to withdraw money. This is riskier for the minor because the sibling's creditors could potentially go after the account, and the sibling could withdraw all the money without the minor's permission. Most banks will not set up a true joint account with a minor without explicit instruction, because custodial accounts are the legal default.

If you want a joint account, you will need to ask the bank specifically for that structure and understand the risks. For most situations—a sibling saving money for a younger sibling's education or future—a custodial account is the safer choice.

What you need to bring to the bank

Bring your own government-issued ID (driver's license, passport, or state ID). Bring the minor's birth certificate or a certified copy. Bring the minor's Social Security number or ITIN. If you do not have legal guardianship, bring written permission from the parent or legal guardian—a notarized letter is safest, though some banks accept an email or phone call if you can have the parent verify it in person or by phone while you are at the bank.

Some banks ask for a second form of ID or proof of address. Call the specific bank branch before you go in and ask what they need. Banks vary widely in their requirements, and showing up unprepared means a wasted trip.

If you are the legal guardian (not just a sibling), bring the court order, custody agreement, or adoption papers that prove it. If the minor is in foster care or under state custody, bring documentation of that status.

When a sibling cannot open an account for a minor

If the minor's parents are alive and have not lost custody, most banks will not let a sibling open an account without the parent's explicit consent. Some banks require the parent to be present. This is a protection against family disputes and kidnapping.

If you are a sibling trying to open an account for a minor and the parent refuses or is unreachable, you cannot force the issue through the bank. The bank's job is to verify that the person opening the account has the legal right to do so. Without that right, they will decline.

If there is a custody dispute or the minor is in state care, the situation is more complex. Talk to the agency or court handling the case before approaching a bank. They can tell you what documentation you need and whether you have the authority to open an account.

Tax implications and reporting

A custodial account is reported on the minor's tax return, not the sibling's. If the account earns interest or investment income, that income belongs to the minor and may be taxable to them. The bank will issue a 1099 form in the minor's name.

The sibling does not report the account on their own taxes and cannot claim the money as a deduction or gift. From a tax perspective, the sibling is straightforward managing the minor's money, not owning it.

If you are concerned about how income from the account will affect the minor's taxes or financial aid for college, talk to a tax professional or the financial aid office before opening the account. Some types of savings can affect aid may be able to access.

Frequently Asked Questions

Do I need the parent's permission if I am the minor's legal guardian?

No. If you have a court order or custody agreement that names you as the legal guardian, you have the same authority as a parent. You can open an account without additional permission. Bring your guardianship documents to the bank.

Can I open an account for a minor without telling the parent?

Legally, no. If the parent has custody, the bank will ask for their consent or require them to be present. If you open an account without the parent's knowledge and they find out, they can ask the bank to close it. This can also create family conflict that is not worth the trouble.

What happens if I put my own money into the account?

The money still belongs to the minor once it is in a custodial account. You cannot take it back out for yourself. If you want to give money to the minor, you are giving it to them, not lending it. Make sure that is what you intend before you deposit it.

Can the minor access the account before they turn 18?

That depends on the bank and the account type. Some custodial accounts let the minor make withdrawals with the sibling's permission. Others restrict access until the age of majority. Ask the bank what the rules are for the specific account you are opening.

What if the sibling dies before the minor turns 18?

The account does not close. The bank will appoint a new custodian or transfer the account to the minor's parent or legal guardian. The money stays in the account and belongs to the minor. Talk to the bank about succession planning if you are concerned about this scenario.