In the United States, banks are required by federal law (the Bank Secrecy Act) to report any cash deposit, withdrawal, or transfer exceeding $10,000 to the IRS via a Currency Transaction Report (CTR). Deposits under this amount do not automatically trigger this report, but, for example, suspicious activity involving amounts over $5,000 can still be flagged.
The majority of banks don't limit how much cash you can deposit, but all institutions have to report deposits of $10,000 or more to the federal government. It's safest to deposit large sums in person, but you could opt for an armored transport for sums greater than $50,000.
In the UK, there is not a threshold amount for deposits that banks must then report to HMRC or police, but rather they are compelled to report any suspicious activity to the National Crime Agency, in the form of a Suspicious Activity Report.
It's not just lump sum cash deposits that can raise flags. Several related deposits that equal more than $10,000 or several deposits over $9,800 can also trigger a bank's suspicion, causing it to report the activity to FinCEN.
When you deposit more than $10,000 in cash, the bank is required to file a Currency Transaction Report (CTR) with the U.S. Treasury. That's not a penalty or a sign of wrongdoing; it's just part of federal banking rules. These reports help track large cash movements that might be tied to tax evasion or illegal activity.
The best thing you can do to avoid the suspicion of illegal activity is to just deposit the money all at once, whether it is a small amount from your daily sales or it is a large amount from a huge sale. Always file the appropriate forms.
A paper trail of potentially suspicious deposits is created after Form 8300 is transmitted to the IRS. Depositing cash at an ATM or with a bank teller, so long as it is below the $10K threshold, will usually not be reported.
There are no federal limits on cash deposit amounts, but deposits over $10,000 trigger mandatory reporting by your bank to the IRS (Form 8300/CTR) for anti-money laundering, requiring identification and documentation for large sums, and structuring (breaking up deposits to avoid reporting) is illegal with severe penalties, even if funds are legal. Banks must also file Suspicious Activity Reports (SARs) for activity over $5,000, so be prepared to explain large, unusual deposits with records of the cash's legal source.
Cash deposit limits
Even if you have more than one personal account with us, the total amount of cash you can pay in across all of them is still £20,000. This limit includes any children's savings accounts you have with us, but doesn't include cash you've paid into any business accounts.
On 1 December 2025 the FSCS deposit protection rose to £120,000. This means that if you hold deposits or savings with a UK-authorised bank, building society or credit union and it goes out of business, FSCS can compensate you up to the new limit of £120,000 per eligible person, per authorised firm.
Can a bank ask where you got the money? Yes, a bank can ask about the source of funds for transactions that they consider to be potentially suspicious. Additionally, if they suspect suspicious activity, they may hold or freeze a bank account until proof of the source of funds is provided.
It is not illegal to keep cash at home in the UK, but it should be stored securely to mitigate risks. The amount of cash to have on hand varies, but a small amount for emergencies is recommended while keeping most in a secure bank account.
Federal regulations require specific reporting when physical currency deposits into your financial institution exceed certain amounts—not to restrict your deposits, but to help combat money laundering and financial crimes. The key number to remember for 2025 is $10,000.
They may ask you questions about the money's origins and you should answer them honestly. You won't be in trouble, but the banks are required to report any deposit over $10K. Don't try to do a bunch of sub-$10K deposits to avoid reporting as that is considered structuring and is illegal.
A trade or business that receives more than $10,000 in related transactions must file Form 8300. If purchases are more than 24 hours apart and not connected in any way that the seller knows, or has reason to know, then the purchases are not related, and a Form 8300 is not required.
You can deposit any amount of cash without being automatically flagged if it's under $10,000 in a single transaction, but banks must report deposits of $10,000 or more to the IRS via a Currency Transaction Report (CTR). While large, legitimate deposits are fine, making multiple deposits to stay under $10,000 (structuring) is illegal and triggers Suspicious Activity Reports (SARs), leading to potential account freezes or law enforcement scrutiny, so transparency with your bank is best for large sums.
Document everything related to your cash transactions, including their business purpose and source. When handling cash exceeding $10,000, allow the bank to file the CTR rather than trying to avoid the paperwork. Businesses receiving over $10,000 in cash for goods or services must also file Form 8300 within 15 days.
There's no legal limit on how much cash you can deposit into a bank account in the UK. But if you're planning to deposit a large sum, your bank might pause to ask where the money came from. This is because they need to follow anti-money-laundering (AML) rules designed to stop financial crime.
Examples of suspicious activity include: Unusual Large Business Deposits of Cash: Large amounts of cash regularly deposited into an account for a company that is not normally a cash business.
Banks must report cash deposits of $10,000 or more. Don't think that breaking up your money into smaller deposits will allow you to skirt reporting requirements. Small business owners who often receive payments in cash also have to report cash transactions exceeding $10,000.
Currency Red Flags
Teller cash frequently exceeds limitation set in the bank's security program. Large volume of cash being deposited into a customer's account whose business would not generate this level of cash. Cash deposit to a correspondent account by means other than armored car.
Under 12 CFR 21.11, national banks are required to report known or suspected criminal offenses, at specified thresholds, or transactions over $5,000 that they suspect involve money laundering or violate the Bank Secrecy Act.
You Made Large Cash Payments or Deposits
Another potential IRS audit trigger is making large cash payments or depositing large amounts of cash in the bank. When any individual or business receives a cash payment of $10,000 or more, they must fill out Form 8300 reporting the transaction to the IRS.