Both the buyer and the seller should get a signed copy of the bill of sale. One original for each side, signed at the same time. The document does different work for each party, and neither can rely on the other to produce it later if a problem comes up.
Why the Buyer Keeps a Copy
The buyer’s copy is proof of two things: that you own the item, and what you paid for it. Both facts feed into obligations that start the moment the sale closes.
- Registration and titling. Most states require a bill of sale to register a vehicle, boat, or other titled property. Without one, the titling agency may refuse to process the transfer. Buyers generally have between 30 and 180 days to complete this step, depending on the state.
- Sales tax. In private-party sales, the buyer pays the sales tax, and most states collect it at registration based on the price listed on the bill of sale. Agencies compare declared prices against fair market value, so understating the number to shrink the tax bill is fraud.
- Insurance. Insurers often ask to see a bill of sale before writing a policy on a newly purchased vehicle or boat.
- Disputes. If the seller later claims the item was stolen, or a lien holder surfaces, the buyer’s bill of sale is the first line of defense.
- Cost basis for taxes. The price on the document establishes what you paid, which matters if you ever sell the item for a gain.
Lose the buyer’s copy and you are reconstructing a number from memory the next time a tax question or title dispute lands on your desk. Not a good position to be in.
Why the Seller Keeps a Copy
Sellers often think the job ends when the money changes hands. It doesn’t. The seller’s copy exists to prove you no longer own the property, which is a different question from who owns it now.
This matters most with vehicles. If the buyer never registers the car in their name and then racks up parking tickets, toll violations, or an accident, those liabilities can follow the registered owner. That is still you until the state’s records say otherwise. Most states allow or require sellers to file a notice of transfer or release of liability with the motor vehicle agency after a sale, and the bill of sale, with its date and the buyer’s information, is your proof that you sold the vehicle and when.
The seller’s copy also carries tax weight. If you sold at a profit on personal-use property, the IRS treats that as a capital gain you have to report.1Internal Revenue Service. IRS Publication 544 – Sales and Other Dispositions of Assets If you sold at a loss, the loss on personal-use property isn’t deductible, but you still need documentation showing what happened to the asset in case the IRS asks.
Who Signs, and Who Drafts It
The seller usually drafts the bill of sale, since they are the party transferring ownership, but no rule requires that. The buyer can prepare it, both parties can work from a template, or for high-value transactions an attorney can draft it. What matters is that the final document is accurate, both parties review it, and both sign it before either side walks away. Each signature happens on each copy, so each party leaves with a fully signed original rather than a photocopy of the other’s.
When Third Parties Also Need a Copy
Some transactions pull in more than two people. A lender with a security interest in the property may want a copy before releasing a lien or approving financing. State motor vehicle agencies typically need one to process a title transfer. If the sale went through an estate, the executor or estate attorney may keep one in the estate file.
In every one of these situations, the signed originals belong to the buyer and seller. Third parties get copies, not originals, unless a specific state law or agency regulation says otherwise. Keep your signed original somewhere safe and hand out photocopies or scans on request.
Extra Rules for Certain Items
The two-copies-and-you’re-done approach covers most private sales, but a few categories carry federal obligations on top of the basic document. If your sale falls into one of these, the paperwork does more than just sit in each party’s files.
Vehicles and Odometer Disclosure
Federal law requires the seller to provide a written odometer disclosure with every vehicle transfer.2Office of the Law Revision Counsel. 49 USC 32705 – Disclosure Requirements on Odometer Rollback The seller must state the cumulative mileage, or disclose that the actual mileage is unknown if the reading is inaccurate. The disclosure usually appears on the title itself, but in some states it shows up on the bill of sale or a separate form. Since 2021, this requirement applies to vehicles for the first 20 model years of life, extended from the previous 10-year window, so a 2011 model-year vehicle still requires disclosure through 2031.3National Highway Traffic Safety Administration. Consumer Alert: Changes to Odometer Disclosure Requirements Vehicles from model year 2010 and older still follow the earlier 10-year rule.
Aircraft
Aircraft transfers require filing FAA Form AC 8050-2 with the Civil Aviation Registry.4Federal Aviation Administration. AC Form 8050-2 – Aircraft Bill of Sale The FAA treats the bill of sale as evidence of ownership and expects it alongside the registration application. Recording fees apply.
Firearms
Federal law does not require a bill of sale or any recordkeeping for private firearm transfers between two unlicensed individuals.5Bureau of Alcohol, Tobacco, Firearms and Explosives. ATF Best Practices: Transfers of Firearms by Private Sellers State rules vary and may add background check, registration, or documentation requirements. Even where no law demands it, the ATF recommends keeping a personal record so you can show ownership if the weapon is later lost, stolen, or recovered.
How Long Each Side Should Keep the Copy
The IRS says to keep records related to property until the statute of limitations expires for the tax year in which you dispose of it.6Internal Revenue Service. IRS Tax Topic 305 – Recordkeeping The standard limitations period is three years from when you filed the return. It stretches to six years if you underreported income by more than 25%, and runs indefinitely if you never filed at all.7Internal Revenue Service. How Long Should I Keep Records
Practically, keep the bill of sale for as long as you own the item, then at least three years after. For vehicles, hold onto it indefinitely. The document takes up almost no space, and the one time you need it, you will be glad you kept it. The same logic applies to the seller’s copy: your proof that you transferred ownership on a specific date doesn’t lose value as years pass.
What to Do If You Didn’t Get a Copy
If the sale already happened and only one of you walked away with the signed document, contact the other party and ask them to sign a duplicate. Both parties have an interest in the paperwork existing, so most sellers and buyers will cooperate once the stakes are explained. If the other side won’t engage, gather whatever secondary evidence you have — payment records, text messages confirming the sale, title transfer paperwork — and consult a local attorney before the next deadline you need the document for arrives.