A safe deposit box key is a flat key, often with a maker’s name and a number stamped on the bow. The number is the box or the lock’s serial, not the bank, so finding the box means paperwork, bank searches and, in the US, the state’s unclaimed property office.
2
keys to open a box: yours and the bank’s guard key
3 years
after the lease ends before California takes unclaimed box contents
$200
Wells Fargo’s fee to drill a box when the keys are lost (2026)
Key takeaways
- Most bank boxes need two keys at once: the renter’s key and a guard key that stays with the bank.
- The number on the key is the box number or the lock’s serial. Mosler said that neither it nor anyone else in the trade records which bank a key belongs to.
- To find the box, look for rent payments on bank statements, the second key and estate papers, then ask the banks and, in the US, search the state’s unclaimed property database.
- Unpaid boxes are opened by the bank. In California the contents go to the State Controller after three years, and owners or heirs can claim them free with no time limit.
- Banks don’t let renters copy keys. A lost key means the bank drills the lock, at the renter’s expense.
In This Article
What a safe deposit box key looks like
It usually turns up in a drawer, a jewellery box or an envelope of papers after a death or a move, and it doesn’t fit anything in the house. The Mosler key in the photo below is a good example of the type: a flat blade with square notches cut along one edge, and a three-lobed bow stamped with the maker’s name and a number. Mosler, which made bank vaults and safe deposit equipment, explained that a number stamped on a safe deposit key gives the box number or the lock’s serial number, nothing more.1
We couldn’t find a maker’s guide that sets out every bow shape and stamp, so treat the table as a set of clues, not a test.
| A flat key with square cuts along one edge, unlike a house key | Matches the Mosler safe deposit key pictured below |
| A lock maker’s name on the bow (Mosler, Sargent & Greenleaf, Yale & Towne, Diebold) | All four made bank locks or safe deposit equipment1,2,3,4 |
| A number stamped on the bow | The box number or the lock’s serial, not the bank1 |
| Two identical keys together | Banks hand renters a pair: Chase’s lease mentions “two safe deposit box keys”, Wells Fargo takes a deposit “for two keys”5,6 |
| A tag or envelope with a branch name or box number | The best lead you’ll get: start with that bank |
| A round shank with a bit at the tip | More likely an old safe, strongbox or door key: see below |
If the key in your hand has a round shank and a bit on the end, it’s more likely to belong to an old safe or strongbox than to a bank box. Our guide to replacement keys for old safes covers those.
Two keys, one box: how the lock works
A bank box is built so that neither side can open it alone. The US bank regulator, the Office of the Comptroller of the Currency (OCC), calls this dual control: “Typically, a bank employee and the customer each have a key, both of which are required to gain entry to the box.”7 The bank’s key is the guard key. Wells Fargo’s lease spells out the other half of the deal: the renter has “the only keys” to the box, and the bank has no way in without them “other than drilling the lock”.6
The idea is older than any bank you’ll be ringing. In 1906 Warren H. Taylor of Stamford, Connecticut, patented for the Yale & Towne Manufacturing Company a changeable key lock “designed more particularly for safe-deposit boxes”, with a guard that required “the presence of a custodian or other person holding a second key”.3
Changeable locks matter because renters come and go. A 1981 Sargent & Greenleaf patent explains that renters often fail to hand their keys back or lose them, and that the lock may be changed between renters even when a key is returned, “to prevent the otherwise possible use of an unauthorized duplicate of the renter’s key”.2 The OCC’s handbook expects the same: surrendered boxes should have their locks changed “even if the customers return the keys”.7 So a key from a box closed years ago may not fit that box any more, even at the right bank.
The boxes themselves sit inside a vault, and the vault door has its own locks, often on a timer: James Sargent’s twin-movement time lock of 1877 is one of the early ones. Our guide to how bank vaults work covers the room around the boxes.
Who made the lock? Reading the bow
The name on the bow tells you who made the lock, not who rented you the box. A maker sold its locks to many banks, so the name alone won’t narrow the search.
Mosler’s answer to owners holding a mystery key was blunt. The numbers “only provide the box number and/or the serial number”, which lets a technician work out how the key is cut, and “We and other members of this industry DO NOT maintain any record of which bank the key belongs to.” It called such a record “a severe breach of security”, and said the American Safe Deposit Association advised vaults against keeping one.1 So a maker can’t tell you the bank, and neither can a locksmith. Since that number can tell a technician how the key is cut, we’d keep it out of photos you post online.
| Mosler | Answered “I have a safe deposit key” questions on its own website in 1999, as quoted above1 |
| Sargent & Greenleaf | Patented safe deposit locks into the 1980s; a lock supplier calls its discontinued 4440 “arguably the most common SD lock in existence”2,8 |
| Yale & Towne | Owned the 1906 guard-key patent above3 |
| Diebold | Built the 1875 vault of the Safe Deposit Company of San Francisco, with 4,600 boxes4 |
For the firms themselves, see our histories of Mosler, the Hamilton, Ohio, safe and vault maker and of Diebold’s safes and bank vaults.
The number on the key identifies the bank.
It’s the box or serial number. Mosler said nobody in the trade records which bank a key belongs to.
The bank keeps a copy of my key.
It keeps a guard key. Wells Fargo says the renter has the only keys to the box.
The contents are insured by the FDIC.
Chase’s lease says they aren’t insured by the bank or the FDIC, and the OCC says banks don’t insure box contents.
How to find the box a key belongs to
We know of no central register of boxes in the US or the UK, so this is a matter of following the paper trail. In roughly this order:
- Bank statements. Box rent is a yearly charge, and banks often take it straight from an account: Chase’s lease lets it debit the rent from any of the renter’s checking or savings accounts.5 A small payment on the same date every year, to a bank, is the clue to look for.
- The second key and its envelope. Keys come in pairs, so the other one may be with the will, in a desk or with a relative, sometimes in an envelope or on a tag with the box number.
- The estate papers. Wills, solicitors’ and accountants’ files, and the post that keeps arriving after a death: rent invoices and late-fee letters are addressed to the renter.
- Ask the banks directly. Start with any bank the person used, as executor or with the legal authority your state or country requires. Banks restrict access after a death until they see the right documents: Wells Fargo denies access until it receives documents showing who has authority, and Chase may let someone with a legal right search a box for a will or burial papers.6,5
- In the US, search unclaimed property. If the rent stopped years ago, the contents may already be with the state. Every state runs a free search, and unclaimed.org links to each one.9,10
- In the UK, ask about safe custody as well as boxes. British banks also held parcels and envelopes in “safe custody”. In one case decided by the Financial Ombudsman, NatWest missed items held for a late customer because they were “orphaned items” not linked to any bank account, so they didn’t show up when the bank searched the accounts.11 Ask for a search of the safe custody records by name, not only the accounts.
One thing that won’t help, sadly, is the key’s maker. Mosler pointed people with “where/who” questions towards the American Safe Deposit Association rather than offer a lookup, because there’s nothing to look up.1
What happens to unclaimed safe deposit boxes
In the US: the bank opens it, the state keeps it
When the rent goes unpaid, the lease ends and the bank can open the box without the renter. The OCC lists unpaid rent among the reasons a bank may open a box without permission, alongside court orders, search warrants, requests from executors and branch closures.7 Chase’s lease describes what follows: after the waiting time set by law, the bank opens the box, lists and stores the contents, may sell them to cover what it’s owed, and may have to hand the contents or the sale money to the state.5
The OCC’s consumer site says a box is likely to be treated as dormant after three to five years with no activity, depending on state law, and that the contents may then go to the state treasurer or unclaimed property office, a process called escheat.10 For most states, the clock starts with the unpaid rent.7
California’s law shows how it works in practice. Box contents pass to the state if unclaimed for more than three years after the lease expired, and the bank must write to the renter 6 to 12 months before they become reportable. The State Controller may sell them at public sale, but not until 18 months after the bank’s report, and military awards, papers and photographs relating to California’s military history can go to the California State Military Museum instead.12 Owners and heirs claim free of charge and with no time limit; an heir finder who does it for you may charge up to 10 percent.13 If the contents have been sold, you’re claiming the money, not the brooch, so it pays to search early.
In the UK: fewer banks, and no state office
British high street banks have mostly left the business. By 2017 Which? reported that almost all the big banks had stopped providing boxes, with Metro Bank the main exception.14 HSBC told the Financial Ombudsman that it began phasing out its service in 2016 and wrote to every box holder.15 American banks are going the same way: Chase’s 2026 lease opens with “We currently do not rent new safe deposit boxes.”5
We couldn’t find a UK equivalent of the American state unclaimed property offices for box contents. In the NatWest case above, items nobody had collected were still in the bank’s safe custody, which is why the bank’s own records are the place to search. Many boxes now sit with independent safe deposit companies, like the Hatton Garden firm whose vault was burgled in 2015; our account of the Hatton Garden heist shows what renters there learned about insurance.
Did you know?
California’s unclaimed property law lets the Controller write separately to anyone whose name is on a savings bond, war bond or military award found in a box, even when the box was rented by someone else.12
Lost keys and drilling: what banks do and charge
If you’re the renter, or the executor, and the keys are gone, the bank drills the lock. Wells Fargo arranges the drilling, replaces the lock and keys, may ask you or your representative to be there, and lists a $200 drill fee, with the renter paying for drilling and a new lock and keys; the key deposit is $20 for the pair.6 Chase drills the lock with the renter present, and the box then has to be emptied and given up.5 Fees vary by bank and change over time, so ask the branch before the appointment.
That’s the whole of the legitimate route. Both leases forbid copying the keys, and a locksmith can’t open a bank’s box for you anyway: the guard key and the vault belong to the bank.6,5 We won’t describe any other way into a box, for the same reason we don’t for safes.
Frequently asked questions
Can you put cash in a safe deposit box?
It depends on the bank. Chase’s lease says not to store money, coin or currency unless it’s collectible, while Wells Fargo’s list of prohibited contents covers weapons, hazardous materials and illegal items but not cash.5,6 Either way, the bank doesn’t insure what’s in the box.7 In the UK, HMRC counts cash kept in a safety deposit box as part of the estate when someone dies.16
What if I lose my safe deposit box key?
Tell the bank where the box is. Without a renter’s key it will drill the lock and fit a new one, and you pay: Wells Fargo’s drill fee is $200 in 2026.
Can a locksmith copy a safe deposit box key?
Banks don’t allow it. Wells Fargo’s terms say “You may not copy your keys”, and Chase renters agree not to duplicate them. Ask the bank for replacement keys or a new lock instead.
Can I find the bank from the number on the key?
No. Mosler said the number gives only the box or serial number, and that lock makers keep no record of which bank a key belongs to. Bank statements and estate papers are better leads.
Who can open a dead person’s safe deposit box?
Whoever the law gives authority to, usually the executor or administrator, once the bank has seen the documents it needs. Some banks allow an earlier search for a will or burial instructions; the rules depend on the state or country and the bank.
Ask us
Not sure what kind of key you’ve found? Send us a photo of the key’s bow and any lock or box it came with and we’ll tell you what we can about the maker and the type of lock. You can cover the stamped number; we don’t need it. We can’t tell you which bank holds a box, and we never open locks or make keys.
Sources:
- Mosler Inc., “Frequently asked questions about Mosler products”, mosler.com, ©1999 (archived 1 March 2000), section “Safe Deposit Boxes”: numbers stamped on safe deposit keys give the box and/or serial number, from which the bitting can be worked out; Mosler and the rest of the industry keep no record of which bank a key belongs to; The American Safe Deposit Association recommends against vaults keeping a record of key serial numbers to rented boxes. ↩︎
- James P. Peppard (assignor to Sargent & Greenleaf, Inc.), US patent 4,290,287, “Double changeable key lock for safe deposit boxes and the like”, filed 28 August 1979, granted 22 September 1981, background section, via Google Patents. ↩︎
- Warren H. Taylor (assignor to the Yale & Towne Manufacturing Company), US patent 814,335, “Changeable combination key lock”, filed 1 July 1905, granted 6 March 1906, via Google Patents. ↩︎
- W. J. Comley and W. D’Eggville, Ohio, the Future Great State: Her Manufacturers (Cincinnati: Comley Bros., 1875), “Diebold, Norris & Co., Safe Manufacturers, Canton, O.”, pp. 432–433, via Internet Archive. ↩︎
- JPMorgan Chase Bank, “Safe Deposit Box Lease Agreement and Privacy Notice”, effective 14 June 2026: “We currently do not rent new safe deposit boxes”; no money, coin or currency unless collectible; contents not insured by the bank or the FDIC; two keys; rent debited from a checking or savings account; lost keys mean drilling with the renter present; termination, sale of contents and transfer to the state; death of a tenant. Accessed 5 November 2026. ↩︎
- Wells Fargo Bank, “Safe Deposit Box Lease Terms”, effective 1 September 2026 (form 597331, rev. 09/26): fee schedule (key deposit $20 for two keys, drill fee $200), “Responsibility for Keys” (the bank holds only a guard key; keys may not be copied; lost keys mean drilling), prohibited contents, and death of a lessee. Accessed 5 November 2026. ↩︎
- Office of the Comptroller of the Currency, Comptroller’s Handbook: Consigned Items and Other Customer Services, version 1.1 (28 December 2018), “Safe Deposit Boxes”, pp. 4–5: dual control (“Typically, a bank employee and the customer each have a key”), locks changed on surrendered boxes, contents not insured by the bank, situations in which a bank may open a box, and footnote 16 on escheat. Accessed 5 November 2026. ↩︎
- MBA USA (lock and safe supplier), “S&G 4440 Safe Deposit Lock, Right Hand, #4 Guard”, product listing (describes the 4440 as “arguably the most common SD lock in existence” and notes it is discontinued). Accessed 5 November 2026. ↩︎
- National Association of Unclaimed Property Administrators, “What is unclaimed property?”, unclaimed.org: lists contents of safe deposit boxes; links to each state’s official program; searching is free. Accessed 5 November 2026. ↩︎
- Office of the Comptroller of the Currency, HelpWithMyBank.gov, “I rented a safe deposit box in 1982, but lost track of it…”: dormancy after three to five years without activity (set by state law), escheat to the state, and searching through unclaimed.org. Accessed 5 November 2026. ↩︎
- Financial Ombudsman Service, final decision DRN-5006543 (National Westminster Bank Plc, safe custody, September 2024): items held for a late customer missed in earlier searches because they were “orphaned items” not linked to any bank account. ↩︎
- California State Controller’s Office, Unclaimed Property Law and Regulations (February 2026), California Code of Civil Procedure §1514 (safe deposit box contents escheat after more than three years; notice 6 to 12 months before) and §1563 (sale by the Controller no sooner than 18 months after the report; military items may be held at the California State Military Museum). Accessed 5 November 2026. ↩︎
- California State Controller’s Office, “California’s Unclaimed Property Program” (brochure): safe deposit box contents among property reported to the SCO; owners and heirs claim free of charge; heir finders may charge up to 10 percent; no time limit to file a claim. Accessed 5 November 2026. ↩︎
- Michael Somerville, “Ask an expert: ‘My bank isn’t providing safe-deposit boxes anymore. Where can I get one?'”, Which?, 16 June 2017. ↩︎
- Financial Ombudsman Service, final decision DRN-4502724 (HSBC UK Bank Plc, safe custody, January 2024): HSBC told the ombudsman it began phasing out its safe deposit box service in 2016 and wrote to all box holders. ↩︎
- HM Revenue & Customs, “Notes to help you fill in form IHT207” (IHT208), December 2005 edition, still hosted on GOV.UK: cash “kept at home or elsewhere, such as a safety deposit box” is part of the estate. ↩︎
