Capital Gains Records: What to Keep When You Sell
Selling an investment takes a few clicks. Proving what you paid for it, years later, can take a whole weekend of digging through old emails. This guide shows you which capital gains records to keep, how to track your cost basis as you go, and how to build a simple file that makes tax time calm instead of frantic.
Key takeaways
- Your taxable gain is the sale price minus your cost basis, so the purchase side of the record matters as much as the sale.
- Cost basis is generally what you paid plus purchase costs, adjusted for things like reinvested dividends and stock splits.
- In the US, keep records for an asset until the period of limitations expires for the year you sell it, generally 3 years after you file that return.
- In the UK, keep contract notes and statements so share pooling and the 60-day property rule are easy to handle.
Late November is a natural moment to think about this. Many people review their portfolios before the year ends, rebalance a fund or two, or finally sell that rental flat or the shares they bought years ago. Every one of those sales creates a record you will need later, and it is far easier to capture the details now than to rebuild them from memory next spring.
The good news: you do not need fancy software or an accountant's filing system. You need to know which documents count, where to put them and how to note the handful of numbers that actually drive your tax bill. Let's go through it step by step.
Why capital gains records matter more than you think
A capital gain is the profit you make when you sell something for more than it cost you. The tax rules look at two numbers: what you received and your cost basis. If you cannot show your cost basis, you may end up paying tax on money that was really just your original investment coming back to you.
Brokers often report a lot of this for you, but not always, and not always correctly. Shares you transferred between platforms, investments you inherited or received as gifts, property, and older holdings are classic gaps. In those cases the record you kept is the record that counts.
The US basics in brief
In the US, assets held one year or less are short-term, and short-term gains are taxed as ordinary income. Assets held longer than one year are long-term, and long-term gains get 0%, 15% or 20% rates depending on your income. That means your purchase date matters just as much as your purchase price, because a few days can move a sale from one category to the other.
Sales are reported on Form 8949 and summarized on Schedule D. Both ask for the date acquired, the date sold, the proceeds and the cost basis for each sale, which is a handy guide to exactly what your records need to show.
The UK basics in brief
In the UK, the capital gains tax annual exempt amount is £3,000 for 2026/27, and gains above that are taxed at 18% or 24%. Shares of the same company are matched under share pooling rules, so you need a clear history of every purchase and sale, not just the most recent one. If you sell UK residential property and there is tax to pay, the gain must be reported and paid within 60 days of completion using HMRC's online service. That is a tight window if your paperwork is scattered.
Common mistake
Throwing away the purchase records once the investment is "settled." The sale is when you need them, and that can be ten or twenty years after you bought. Purchase paperwork should live as long as you own the asset, plus the retention period after you sell.
What to keep for each type of asset
Different assets leave different paper trails. Here is what is worth saving for the most common ones.
Shares, funds and ETFs
- Trade confirmations or contract notes for every purchase and sale, showing the date, quantity, price and fees.
- Annual and year-end statements from each broker or platform.
- Records of reinvested dividends, because each reinvestment is a small new purchase that adds to your basis.
- Notices of stock splits, mergers and spin-offs, which change the number of shares you hold and how your basis is spread.
- Transfer statements if you moved holdings between brokers, since basis information does not always travel with them.
Property you do not live in
For a second home, a holiday cottage or let property, keep the purchase contract, closing or completion statement, legal and survey costs, and records of improvements you made over the years. Improvements can raise your cost basis, while ordinary repairs usually do not. If you rent the property out, depreciation records matter too. (Your main home has its own rules, which we cover in a separate guide.)
Inherited and gifted assets
Assets you receive as an inheritance or a gift follow special basis rules that differ between the US and UK. Keep any valuation, probate or estate paperwork and a note of the date you received the asset. Ask the executor or the giver for their records while it is still easy to do.
Other valuables
Collectibles, a share in a private business or digital assets can also trigger capital gains. Crypto in particular needs its own tracking system, which we cover separately. For the rest, keep the receipt, any valuation and proof of costs you added.
Pro tip
Download your broker statements as PDFs every January, even if you are not selling anything. Platforms change, merge and close, and old statements can become hard to access. A yearly download habit takes ten minutes and saves hours later.
How to work out and track your cost basis
Cost basis is generally what you paid for the asset plus the costs of buying it, such as commissions or fees. Over time it is adjusted for things like reinvested dividends and stock splits. Keeping a running basis figure as you go is much easier than reconstructing it at the end.
- Start a holding record. Create one row or one page for each investment you own, with its name and the account it sits in.
- Log every purchase. Record the date, quantity, price per unit and fees. Add them up to get the cost of that purchase.
- Add reinvestments. When dividends are reinvested, log each one as a new purchase with its own date and amount.
- Adjust for corporate actions. After a split, update the share count. Your total basis usually stays the same, but the basis per share changes.
- Record each sale. Note the date, quantity, proceeds and selling fees, and which purchase lots the sale came from if your broker lets you choose.
- Calculate the gain. Proceeds minus selling fees, minus the basis of the shares you sold, equals your gain or loss.
- Save the evidence. Link or file the confirmations that back up every number in your record.
Example
Imagine Leah, a freelance copywriter in Ohio. She bought 50 shares of a fund for $2,000 plus a $10 fee, then had $90 of dividends reinvested over two years. Her basis is $2,000 + $10 + $90 = $2,100. In December she sells all the shares for $2,600 and pays a $10 fee. Her gain is $2,600 minus $10 minus $2,100, which is $490. Because she held the fund for more than a year, it is a long-term gain. Without the reinvestment records, she would have overstated her gain by $90. (These numbers are made up for illustration.)
A simple capital gains log template
Copy these columns into a spreadsheet and add one row per sale. Keep a separate tab for purchases if you buy the same investment many times. The rows below are made-up examples, not real trades.
| Asset | Account | Date bought | Date sold | Quantity | Cost basis (incl. fees) | Proceeds (after fees) | Gain or loss | Holding period | Evidence filed |
|---|---|---|---|---|---|---|---|---|---|
| Example index fund | Broker A | 2023-03-14 | 2026-12-08 | 50 | $2,100 | $2,590 | $490 | Long-term | Yes, 2026 folder |
| Example tech share | Broker B | 2026-02-02 | 2026-11-20 | 20 | $1,500 | $1,380 | -$120 | Short-term | Yes, 2026 folder |
| Example UK share | Platform C | 2019-06-10 | 2026-12-01 | 300 | £900 | £1,350 | £450 | Pooled | Contract notes saved |
For UK shares, your pooled basis is the average cost of all the shares of that company in your pool, adjusted for the matching rules on shares bought around the time of a sale. A tidy purchase tab makes that calculation straightforward, or lets an accountant do it quickly.
How long to keep capital gains records
This is where people most often throw things away too soon. The clock does not start when you buy. It starts when you sell and report the sale.
- US: the IRS says to keep records relating to property until the period of limitations expires for the year you dispose of it. That is generally 3 years after you file the return reporting the sale. So shares bought in 2012 and sold in 2026 need their 2012 purchase records until at least 2030.
- UK: keep contract notes, statements and calculations for as long as you own the asset, then for the record-keeping period HMRC sets for the tax year of the sale. Check gov.uk for the period that applies to your situation.
Many people simply keep investment purchase records forever in digital form. Scanned files take almost no space, and it removes any guesswork about when it is safe to delete.
Common mistake
Relying only on your broker's online history. Platforms may limit how far back you can see, and basis figures for transferred or very old holdings are sometimes missing or marked as unknown. Your own saved copy is your safety net.
Set up a capital gains file in one afternoon
Here is a simple folder structure that works for most households and small business owners:
- Holdings: one subfolder per account, holding purchase confirmations and transfer statements for everything you still own.
- Sales by year: one subfolder per tax year with sale confirmations, your gains log and the broker's year-end tax form.
- Property: one subfolder per property with the purchase file, improvement invoices and, later, the sale file.
- Notes: a short text file explaining anything unusual, such as an inheritance date or a fund merger.
Back up the whole folder in two places, for example cloud storage and an external drive. Use clear file names like "2026-12-08 Broker A sale index fund.pdf" so you can search later.
Pro tip for year-end sellers
If you plan to sell before 31 December, check your holding period first. Selling a few weeks after the one-year mark instead of a few weeks before can change how a US gain is taxed. Make the decision on purpose, not by accident.
A quick note: this article is general information about record keeping, not tax or investment advice. Capital gains rules have many details and exceptions, so speak with a qualified tax professional about your own situation, and check IRS.gov or gov.uk for the current rules for 2026 and 2026/27.
Your capital gains records checklist
- List every account where you hold investments or property
- Download purchase confirmations and year-end statements for each one
- Start a holding record with dates, quantities, prices and fees
- Add reinvested dividends and adjust for any stock splits
- Log each sale in a gains template with the holding period
- Keep property purchase files and improvement invoices together
- Back up the folder in two places
- Diary the date each sale's records can be reviewed for deletion
Frequently asked questions
What if I cannot find the purchase record for an old investment?
Start with the broker or fund company, which may be able to supply historical statements. Old emails, bank statements showing the payment and annual tax forms can also help piece it together. If you still have gaps, a tax professional can advise on reasonable ways to support your figures.
Do I need records if my broker already reports my cost basis?
Yes. Broker figures can be incomplete for transferred, inherited or older holdings, and you are responsible for the numbers on your return. Keep your own copies so you can check the broker's figures and fix errors.
Should I keep records for investments I sold at a loss?
Absolutely. Losses can often be used against gains, so the records supporting a loss are just as valuable as those for a gain. Keep them for the same period.
Is a spreadsheet enough, or do I need software?
For most people a spreadsheet plus saved confirmations is plenty. If you trade often or hold many accounts, portfolio or tax software can save time. Check current features, pricing and privacy policies before connecting any account.
Related reading
The bottom line
Good capital gains records come down to a simple habit: save the proof every time you buy, adjust your basis when something changes, and log each sale with its dates and fees. Keep it all until well after you report the sale, and back it up.
Spend one afternoon before the year ends setting up your folders and gains log. The next time you sell, you will know your numbers in minutes, and tax season will feel a lot lighter.
