To green up, you place a closing bet on the other side of the same selection, sized so you finish with the same result whichever way the event goes. After a back, lay stake = back stake x back odds / lay odds. Backed for $50 at $6.00 with $4.00 now available to lay, you lay 50 x 6.00 / 4.00 = $75 and lock in $25 whichever runner wins, before commission (illustrative prices).
Greening up is also called trading out, and the same sum at a worse price locks in a loss, which traders call a red up. Australian law allows online bets on a sport only before the game begins (Interactive Gambling Act s 8A(3), with the definition in s 10B). A sports green up therefore has to be done by the start, and every racing position here is closed before the jump.
The green up formula after a back or a lay
There are two versions, depending on which bet came first:
| You opened with | You close with | Closing stake | Locked result |
|---|---|---|---|
| A back | A lay | back stake x back odds / lay odds | lay stake - back stake |
| A lay | A back | lay stake x lay odds / back odds | lay stake - back stake |
The result is a profit when the closing price is better than the opening one (shorter after a back, longer after a lay) and a loss when it is worse.
Both versions come from one rule, which also sizes any equal profit hedge on an exchange. From any position on one selection, write down what you make if it wins and if it loses. Then:
closing stake = (result if it wins - result if it loses) / closing price
Place it as a lay when the win result is the bigger one. When the lose result is bigger, place a back of (result if it loses - result if it wins) / closing price instead. For a $50 back at $6.00 the rule gives (250 - (-50)) / 4.00 = 300 / 4.00 = $75, the same as the first formula.
Green up example: a $50 back at $6.00 closed at $4.00
Example: illustrative prices for an imagined race. You backed Runner 6 for $50 at $6.00. It has firmed to $4.00 on the lay side, 20 ticks shorter, and you lay it for 50 x 6.00 / 4.00 = $75.
| Result | Back $50 at $6.00 | Lay $75 at $4.00 | Market total |
|---|---|---|---|
| Runner 6 wins | 50 x 5.00 = +$250.00 | 75 x 3.00 = -$225.00 | +$25.00 |
| Any other runner wins | -$50.00 | +$75.00 | +$25.00 |
The lay's liability is 75 x (4.00 - 1) = $225, less than the $250 the back wins, and its $75 stake is more than the $50 the back loses, which is how both results end up positive. Before the lay, your worst case in the market was the $50 stake; after it, your exposure in that market falls to zero.
Without the lay you hold a $50 bet at $6.00 on a runner now priced at $4.00: +$250 or -$50. The green swaps that for $25 either way. It is a choice, not an upgrade: you give up the bigger win to remove the loss.
Skip the full green when you would still back Runner 6 at $4.00 for $50 now, because the $75 lay is then a bet against your own view; a partial green fits better. Skip it too when the best lay sits several ticks above the best back: that gap comes straight out of the locked result.
Risk: Betting involves risk. The $25 exists only if the whole lay is matched at $4.00 before the jump, and a price that moves first leaves a smaller green or a loss. See responsible gambling for limits and support.
Commission on the green book
The exchange takes commission from what you win across a whole market, net of what you lose in it, and the rate is its own to set and change, so use it as an input. A green book wins the same amount in every result, so it pays the same commission whatever happens. At an illustrative 8%:
| Result | Market total | Commission at 8% | You keep |
|---|---|---|---|
| Runner 6 wins | +$25.00 | 25 x 0.08 = $2.00 | $23.00 |
| Any other runner wins | +$25.00 | 25 x 0.08 = $2.00 | $23.00 |
That is why the green up formula needs no commission term when both bets are in the same exchange market. A red up pays none at all, because the market finishes behind. Exchange commission explained covers how the rate is applied.
It is different when the first bet was at a bookmaker. Only the exchange lay then pays commission, on its own winnings, so the equal-result lay becomes back stake x back odds / (lay odds - commission rate) = 300 / 3.92 = $76.53, for $20.41 either way instead of $23.00. Hedging bets covers bookmaker hedges in full.
Greening up a loss: the red up
If the price moves against you, the same formula fixes the loss instead. Say Runner 6 drifted from $6.00 to $8.00, 10 ticks longer:
lay stake = 50 x 6.00 / 8.00 = $37.50, with a liability of 37.50 x 7.00 = $262.50
| Result | Back $50 at $6.00 | Lay $37.50 at $8.00 | Market total |
|---|---|---|---|
| Runner 6 wins | +$250.00 | -$262.50 | -$12.50 |
| Any other runner wins | -$50.00 | +$37.50 | -$12.50 |
The red up turns a bet that could lose $50 into a fixed $12.50 loss, with no commission to pay. Whether to take it was decided when you set your stop: a red up at the stop price is the plan working, not a failure.
Risk: Betting involves risk. A red up fixes the loss only at the price you actually get, and in a fast drift the lay can be matched longer than you planned, making the loss bigger. See responsible gambling for limits and support.
It works the same way after a lay. With illustrative prices, you laid $36 at $3.50, a liability of 36 x 2.50 = $90:
| Close with a back at | Back stake | If the runner wins | If it loses |
|---|---|---|---|
| $4.20, after a drift (green) | 36 x 3.50 / 4.20 = $30.00 | -90 + 30 x 3.20 = +$6.00 | 36 - 30 = +$6.00 |
| $3.00, after a firm (red) | 36 x 3.50 / 3.00 = $42.00 | -90 + 42 x 2.00 = -$6.00 | 36 - 42 = -$6.00 |
Partial green ups
A partial green up closes only part of the position, so one result stays bigger than the other. Using the $50 back at $6.00 and lays at $4.00, where each lay's liability is three times its stake:
| Lay at $4.00 | If Runner 6 wins | If it loses | What it does |
|---|---|---|---|
| None | +$250.00 | -$50.00 | The open bet |
| $25.00 | 250 - 75 = +$175.00 | -50 + 25 = -$25.00 | Halves the possible loss |
| $50.00 | 250 - 150 = +$100.00 | -50 + 50 = $0.00 | Covers the stake |
| $60.00 | 250 - 180 = +$70.00 | -50 + 60 = +$10.00 | Something either way, more on the runner |
| $75.00 | 250 - 225 = +$25.00 | -50 + 75 = +$25.00 | The full green |
| $90.00 | 250 - 270 = -$20.00 | -50 + 90 = +$40.00 | Too far: now a bet against the runner |
Commission comes off whichever result is positive in the outcome that happens. At an illustrative 8%, the $50 lay's +$100 becomes 100 x 0.92 = $92 if Runner 6 wins, and its $0 pays nothing.
Pick the lay stake from the result you want in the outcome you care about. To finish level if any other runner wins, lay the back stake. To bank something either way while keeping more on the runner, lay between that and the full green. Laying more than the full green stake turns the trade into a lay of the runner.
Risk: Betting involves risk. Laying less than the back stake leaves a loss if Runner 6 loses, and each row holds only if its lay is matched in full at $4.00 before the jump. See responsible gambling for limits and support.
When a green up does not go as planned
- Part matched. You ask to lay $75 at $4.00 and $40 is matched, so Runner 6 winning gives 250 - 40 x 3.00 = +$130 and losing gives -50 + 40 = -$10. Finish with the one-rule formula, (130 - (-10)) / closing price. At $4.00 that is the $35 still waiting, at $3.50 it is 140 / 3.50 = $40 for +$30 either way, and at $5.00 it is 140 / 5.00 = $28 for +$18 either way.
- Unmatched at the jump. Whatever is still waiting when the jump comes follows that order's setting (lapse, take SP or keep), so a half-finished green is still partly a bet. Unmatched bets explains the settings.
- A scratching. If another runner is scratched after your bets are matched, the exchange's rules can cut the odds of bets already matched on the remaining runners, and that can leave a green uneven. Recheck both results and even them with the one-rule formula. If your own runner is scratched, expect its bets to be cancelled.
- Several runners. If you hold positions on more than one runner, green each runner on its own, and the market total is then the same whatever wins.
- Small amounts. Exchanges set a minimum bet in their terms and stakes round to the cent, so a very small green can leave a few cents between results.
Mistakes that leave a green uneven
With the same illustrative $50 back at $6.00:
- Using the back price. A back position closes with a lay, so the price that counts is the best price available to lay. If the market shows $3.90 to back and $4.00 to lay and you size the lay at $3.90 (300 / 3.90 = $76.92), it is matched at $4.00: +$19.24 if Runner 6 wins and +$26.92 if it loses.
- Typing the liability as the stake. Entering 75 as the liability lays a $25 stake (75 / 3.00), which leaves +$175 or -$25: still mostly a bet.
- Using the exchange formula on a bookmaker bet. A $75 lay against a bookmaker back pays commission only when the lay wins, so at 8% it gives +$25.00 if the runner wins but -50 + 75 x 0.92 = +$19.00 if it loses.
- Forgetting bets you already hold. The green has to cover your whole position on that runner, not only the latest bet.
- Leaving it to the last seconds before the jump, when an unmatched lay turns the trade back into a bet.
How to green up step by step
- Find the best price on the side you are closing: the lay side after a back, the back side after a lay.
- Work out the closing stake with the formula or the hedge calculator.
- Work out both results by hand. They should match to within a few cents.
- Check that the slip shows a stake, not a liability, then confirm.
- Check the matched amount, and finish any remainder with the one-rule formula.
Some exchange screens and trading tools have a one-click close that sizes the bet. Before you rely on one, check whether it uses the best available price, whether it evens the results before or after commission, and what it does with any part left unmatched. A cash out button offered before the start does the same job for one figure; is cash out worth it compares that figure with a close you size yourself.
What B337 shows before you close
B337 has no back or lay placement on the exchange, so every green up here goes on in your own exchange account. Its Terminal sets prices from 40+ bookmakers across racing and sports next to Betfair's back and lay columns, with flucs that show whether a runner has been firming or drifting. Those prices arrive on a repeating cycle rather than with every tick, so take the closing price from the exchange itself. Bookmaker names are trade marks of their owners. B337 is not affiliated with them.
For laying and liability from the beginning, start with lay betting explained; Betfair trading explained shows the trades a green up closes.
Risk: Betting involves risk. A green up locks in a result only once both bets are fully matched, a late scratching can unbalance it, and there is no guarantee of profit. See responsible gambling for limits and support.