Which Broker Records Do You Need for UK Capital Gains Tax?

To calculate UK capital gains tax on shares, you need your broker's transaction history, going back to the first purchase of everything you sold. The annual tax documents brokers send are useful, but none of the three platforms below gives you a figure worked out on HMRC's rules. Hargreaves Lansdown's tax certificate covers income only. Interactive Brokers matches sales first in, first out over a calendar year. Trading 212 uses a weighted average cost.

HMRC matches each sale with shares bought the same day, then with shares bought in the next 30 days, and only then with the average cost of everything else you hold (the Section 104 pool). It does this in sterling, across all your accounts, for the tax year running from 6 April to 5 April. A broker document built on any other basis can be a good cross-check, but it is not your computation.

Broker records compared

Sources: HL's tax certificate help and adviser centre, Interactive Brokers' year-end reports for non-US clients, and the Trading 212 help centre articles on annual statements and weighted average cost. Brokers change their documents, so check the current version in your account.

Why a broker's annual figure is not your CGT figure

Four differences explain most of the gap between a broker statement and an HMRC calculation:

1. Matching rules. First in, first out and simple average cost both ignore the same-day rule and the 30-day rule. If you sold and bought back within 30 days, the cost HMRC uses can be very different.
2. The year. Interactive Brokers reports the calendar year. Sales between 1 January and 5 April belong to the previous UK tax year.
3. Currency. HMRC converts each purchase and sale to pounds on its own date. A profit in dollars or in a base currency other than sterling can be a different number, or even a loss, in pounds. The US shares guide works through an example.
4. One account only. Your Section 104 pool includes every share of the same class you own, wherever it is held. A broker cannot see purchases made elsewhere or shares transferred in with their original cost. See using several brokers.

Hargreaves Lansdown

HL issues a consolidated tax certificate with the Spring investment report for a Fund and Share Account or Active Savings account that received taxable dividends or interest. There is none for an ISA or SIPP. The certificate lists income and tax deducted. It includes income on accumulation units, which is reinvested inside the fund and does not appear as cash in your income transaction history. Keep it for the income pages of your tax return.

HL does not produce a capital gains figure. Its adviser centre says plainly: "We cannot calculate any capital gains." Instead, it can provide a Stock Movement Report on request, listing purchases, sales, conversions, corporate actions and transfers.

For the calculation, download the Capital transaction history as a CSV from My accounts, with a date range starting at your first purchase. The amounts are already in sterling, including overseas shares, because HL converts foreign deals into pounds. Our Hargreaves Lansdown guide shows each step and the columns to expect. If your account goes back further than the online history you can download, a Stock Movement Report covering the account from the start fills the gap. FiscalFox's HL importer reads that report in CSV form too.

Interactive Brokers

Interactive Brokers offers non-US clients an Annual Statement, a Dividend Report and a Forex Income Worksheet. The Annual Statement shows realised profit and loss matched "on a First In, First Out (FIFO) matching basis or the specific method of tax accounting selected for your account." Figures are in your account's base currency, and the reports cover the calendar year. The Forex Income Worksheet follows US rules. None of the year-end reports mentions HMRC, and Interactive Brokers says it "does not provide tax advice".

For the calculation, run an Activity Statement from Performance & Reports, Statements, with a custom date range, and download it as a CSV. It lists individual trades with their currency, commission and realised profit, plus dividends and interest. IBKR keeps daily and custom statements for the four previous calendar years and the current year, so if your first purchases are older, use statements you saved at the time or ask IBKR what it can provide. Our Interactive Brokers guide covers the export and the Flex Query alternative.

Trading 212

Trading 212 lets you generate an annual statement in the app under Documents, Account statements, Annual statements. It is not available for ISAs, and a statement for the current tax year can only be produced after the account has been closed. Trading 212 does not describe what the UK statement contains. Its help centre says it uses a weighted average cost "to comply with tax and reporting requirements," and it states: "We do not deduct any capital gains tax on profits."

A weighted average is close to the Section 104 pool, but it skips the same-day and 30-day rules. If you trade the same share often, the difference matters. For the calculation, export your History as a CSV (Menu, History, then the export button), choosing transactions from your first purchase. The file includes a sterling Total for each trade, the exchange rate, any currency conversion fee, and a Result column. That Result is Trading 212's own average-cost figure, not an HMRC one. Our Trading 212 guide explains which columns matter.

Can you use HMRC's shares calculator instead?

HMRC has a free capital gains calculator for shares, but it is designed for one simple sale. GOV.UK says you can use it if the shares you sold were the same type, acquired in the same company on the same date, and sold at the same time. You cannot use it if you:

• sold other shares in the tax year;
• sold other chargeable assets in the tax year, such as a property you let out;
• claim any reliefs; or
• are a company, agent, trustee or personal representative.

If you bought the shares in several purchases, sold more than one holding, or rebought within 30 days, you need to work through the matching rules yourself, ask an accountant, or use a tool that applies them to your full history.

What HMRC expects you to keep

GOV.UK asks you to keep records of what you paid, what you received and any costs, including contract notes from stockbrokers, for at least a year after the Self Assessment deadline (see record keeping on GOV.UK). If you complete the SA108 capital gains pages, HMRC also asks for your computations. A transaction export plus the working that turns it into gains and losses covers both.

Checklist before you calculate

• A transaction export from every broker where you hold or held a taxable (non-ISA) account.
• Each export starting from the first purchase of anything you sold, not just this tax year.
• Details of shares transferred between brokers, with their original purchase dates and costs.
• Corporate actions such as splits, mergers and spin-offs, which can change the number or cost of shares.
• Your broker tax certificates, kept for the income pages and as a cross-check.

How FiscalFox uses these files

FiscalFox reads the transaction exports named above, combines files from different brokers into one timeline, converts foreign-currency trades on their own dates, and applies the same-day, 30-day and Section 104 rules for each UK tax year. It does not read tax certificates or annual statements, because they do not contain the trade-by-trade detail the calculation needs. The calculation is free. The optional report pack includes the disposal-by-disposal computations for SA108.