Imagine opening your banking app to find a surprise $150,000 deposit. You didn’t earn it or inherit it and yet there it is.

​While this scenario may seem far-fetched, glitches happen. Even big banks like JPMorgan Chase (1) and Bank of America (2) have had high-profile cases where customers saw the wrong amounts in their accounts.

Thanks to Jeff Bezos, you can now become a landlord for as little as $100 — and no, you don't have to deal with tenants or fix freezers. Here's how

This 20-year-old lotto winner refused $1M in cash and chose $1,000/week for life. Now she’s getting slammed for it. Which option would you pick?

Dave Ramsey warns nearly 50% of Americans are making 1 big Social Security mistake — here’s what it is and the simple steps to fix it ASAP

​Let’s consider a hypothetical story to better understand how this rare-yet-possible situation plays out: Kevin is a 35-year-old warehouse supervisor who spent the last decade treading water financially.

He’s carrying $28,000 in credit card debt, $19,000 on a car loan and $42,000 in student loan debt. His credit score is bruised and he has no savings. In this precarious position, any unexpected expense pushes him closer to a full-blown financial crisis.

​An unexpected $150,000 windfall could wipe the slate clean and help him gain solid financial ground. Now he’d finally feel like he’s “adulting” with an emergency fund and retirement portfolio.

​For someone who has never felt financially secure, it’s understandable why Kevin would welcome this financial lifeline. Of course, the problem is that Kevin knows the money isn’t his. The deposit came from an unknown source and, in all likelihood, is a mistake rather than an unexpected gift.

​He hasn’t called the bank yet, but he hasn’t touched the money either.

​So, does he keep it or report it? Here’s what the law says. ​

​Deep down Kevin knows he can’t keep the money. An accidental deposit doesn’t become yours just because it appeared in your account. In the eyes of the law, that money still belongs to the person or institution it came from and spending it comes with serious financial consequences — and legal ones too.

Keeping money sent to you by mistake is usually covered by a legal principle called unjust enrichment. In simple terms, if you receive funds in error, you’re required to return them because keeping them would unfairly benefit you at the sender’s expense (3).

​When a deposit is credited into an account by mistake, can the bank take it back? The Consumer Financial Protection Bureau (CFPB) answers the question plainly: Yes (4).

If Kevin were to use the funds to pay off his debts, the bank would reverse the transaction once the error was discovered. Whenever that day comes, the $150,000 would be pulled back out of his account. If the balance isn’t there anymore, he’d be left owing the bank the full amount like any other unpaid debt (plus potential fees and overdrafts) and damage his banking history.

This could trigger the bank to freeze your account or your wages to be garnished and more (5). In some cases, knowingly spending money that isn’t yours can trigger fraud or theft allegations, since the key factor becomes intent once you realize the mistake.

​The U.S. Department of Justice states that fraud offenses require proof of “specific intent to defraud” (6). In this case, it’s hard to argue that Kevin doesn’t know the money isn’t his. So, if he acts as if it's his and then gets caught, he’s not going to have much of a case in court.

​There’s also a practical reality: Banks track transfers meticulously, especially large and unexplained deposits. Data from FinCEN shows that there were roughly 27.5 million Suspicious Activity Reports (SARs) in 2024, or just under 75,500 per day (7).

​Kevin might also feel like he has time to decide, but even that isn’t entirely true. Plus, there’s no anonymity on a bank account. The longer he waits to report it, the worse it’ll look.

​Sure, it will feel like a major bummer, but the only correct response is to notify the bank immediately and leave the money untouched. Doing so will create a record that Kevin acted in good faith and protect him from possible allegations.

​Note that these rules also apply to the increasingly common “accidental transfer” scams on payment apps, which the Federal Trade Commission (FTC) says rose to 90,571 reports in 2024 (8).

​In this scheme, someone sends you money and quickly contacts you to request a refund via a different method, such as Zelle or Cash App. If you send money back and keep the original transfer, it will later get reversed as fraudulent. So, in this case, you lose both the money you sent to the fraudster and the money you thought you got accidentally.​

Read More: 5 essential money moves to make once you’ve saved $50,000

Read More: Young millionaires are ditching stocks. Why older Americans should take note

​Once you notice a deposit you didn’t initiate, contact your bank directly to explain the situation. To make this process run more smoothly, collect details in advance, such as transaction IDs, the transfer date and any sender information, so you’re prepared.

​If someone contacts you directly asking for a refund, you should never comply; deal directly with the bank by contacting them through a verified number (ideally from within your banking app).

​Once reported, the bank will document the error and then investigate the source of the funds. Once they realize what happened, they’ll reverse the transaction out of your account.

After the reversal, keep a close eye on your account to ensure you don’t get charged. If fees appear on your account, call the bank again and request they be waived.

While all this work may not feel all that heroic, it’s a real win for your future. Trying to spend that money would only lead to legal and financial problems down the road. However, reporting the deposit and leaving it alone protects your credit and legal standing so you can continue toward your financial goals one realistic step at a time.

Taxes are going to change for retirees under Trump’s ‘big beautiful bill’ — here are 4 reasons you can’t afford to waste time

Robert Kiyosaki begs investors not to miss this ‘explosion’ — says this 1 asset will surge 400% in a year

Vanguard reveals what could be coming for U.S. stocks, and it’s raising alarm bells for retirees. Here’s why and how to protect yourself

Turning 50 with $0 saved for retirement? Most people don’t realize they’re actually just entering their prime earning decade. Here are 6 ways to catch up fast

Join 250,000+ readers and get Moneywise’s best stories and exclusive interviews first — clear insights curated and delivered weekly. Subscribe now.

We rely only on vetted sources and credible third-party reporting. For details, see our editorial ethics and guidelines.

CNBC (1); CNN (2); Cornell Law School (3); Consumer Financial Protection Bureau (4, 5); U.S. Department of Justice (6); CATO Institute (7); Federal Trade Commission (8)

This article provides information only and should not be construed as advice. It is provided without warranty of any kind.