Realised P&L is the gain or loss already booked on positions sold or redeemed, unrealised P&L is the mark-to-market on what is still held, and the portfolio view keeps the two apart before adding them to a single total.
Two kinds of profit and loss
A portfolio can gain or lose in two different ways, and the portfolio view keeps them apart. Realised P&L is the gain or loss booked on a position that has actually been sold or redeemed: the money is settled and the outcome is fixed. Unrealised P&L is the difference between the market value of a position still held and the cost basis of that holding: it moves with the price every day until the position is sold, at which point it becomes realised. The profit and loss table on the portfolios index shows both, per portfolio, with income beside them.
The distinction appears at two levels on the site. The portfolios index sums it per portfolio in its profit and loss table; a single portfolio's detail page carries a P&L view of its positions table, with columns for cost basis, unrealised, realised, income and total for each holding. The same arithmetic runs at both levels, so the sum of the holdings' figures reconciles to the portfolio's total, and the portfolio totals reconcile to the account.
Worked once, on one holding
The table below runs a single holding through both figures with round numbers that are illustrative and not from any portfolio or report. It buys £10,000 nominal, sells half, keeps the rest, and receives one coupon.
| Event or figure | Amount | Working |
| Bought £10,000 nominal at a dirty price of 98.00 | −£9,800.00 | cost basis of the whole holding |
| Sold £5,000 nominal at a dirty price of 101.00 | +£5,050.00 | proceeds |
| FIFO cost of the half sold | £4,900.00 | half of £9,800.00 |
| Realised P&L on the sale | +£150.00 | £5,050.00 − £4,900.00 |
| Remaining £5,000 valued at £102.00 | £5,100.00 | market value still held |
| Cost basis of the half held | £4,900.00 | half of £9,800.00 |
| Unrealised P&L on the rest | +£200.00 | £5,100.00 − £4,900.00 |
| Income received | +£100.00 | coupon paid to date |
| Total gain or loss | +£450.00 | £200.00 + £150.00 + £100.00 |
The realised £150 is money already banked from the sale; the unrealised £200 would only become money if the remaining half were sold at the valuation used. The two are shown separately for exactly that reason: one is settled, the other is a price on a position still held.
How realised P&L is worked out
Realised P&L is computed on a first-in, first-out basis: the units bought first are treated as the ones sold first, so a sale is matched against the oldest purchase's cost. That is why the half sold above is relieved at half the original cost basis rather than at any later price. Once a position is fully sold or redeemed it leaves the open positions, and its realised result is kept in a folded closed-positions row beneath the table, with its own realised P&L, income and contribution to the total, so the record of a completed holding is not lost when the holding is.
A redemption is a realised event just as a sale is: when a gilt matures, the position closes and the difference between the principal returned and its cost basis is realised without a trade needing to be booked, only the redemption happening. Income received sits outside both, because a coupon is neither a gain on the position's price nor a mark-to-market of it; it is cash paid while the position is held.
Total gain or loss, and why it is not the IRR
- Unrealised P&L — the mark-to-market on the positions still held.
- Realised P&L — the gain or loss on positions sold or redeemed.
- Income received — the coupons paid while positions were held.
The total gain or loss adds the three together: unrealised P&L, realised P&L and the income received. That total is a pound figure on the position, settled and unsettled money combined. It is not the same as the IRR since inception, which is a rate — the annualised, money-weighted return over every cash flow in and out of the portfolio. Realised P&L answers how much has been won or lost on the parts that have been closed; the IRR since inception answers what annual rate the portfolio has earned on the money put through it. A portfolio can have a large unrealised gain and a small realised one, or the reverse, and the two rates and figures describe different spans of activity.
The attribution tab on a gilt's own page, reached from the conventional gilts list, splits a held position's return into the parts that moved it over a chosen window. That is a decomposition of a return, not a profit-and-loss split between realised and unrealised; it explains how a value got from one point to another, whether or not the position has been sold.
Background, not advice
This explains what separates realised from unrealised P&L and how the portfolio view builds a total from both; it is general background, not investment, tax or legal advice for any reader's circumstances. The figures above are illustrative, and the figures for a real portfolio are computed from its booked trades and marked at the day's report. An unrealised gain is a price on a holding, not money in hand, and it can move before anything is sold.