Lay betting is profitable only when you lay runners at prices shorter than their true chance of winning justifies, by more than the commission the exchange takes from winning lays. Laying in itself has no edge. A fairly priced lay above $2.00 wins more often than it loses, which makes a record look healthy, but each loser pays out a liability that can be several times the stake a winner collects.
At $3.00 with an illustrative 6% commission, a lay record needs 68.0% winners just to break even, and 67 winners from 100 lays finishes $30.20 behind (hypothetical prices, worked below).
Why lay strike rates look high
A lay wins whenever the runner loses, and in any race with three or more runners most of them lose. A fairly priced $9.00 runner loses 1 - 1 / 9.00 = 88.9% of the time. A layer of runners like it wins eight bets in nine and still makes nothing before commission, because the ninth pays out eight times the stake: 8 x $1 - 1 x $8 = $0 for every $1 of lay stake.
What matters is the strike rate against its break-even line, and commission moves that line up. A winning lay keeps (1 - commission rate) of its stake and a losing one pays (lay odds - 1), so:
break-even strike rate = (lay odds - 1) / ((lay odds - 1) + (1 - commission rate))
At an illustrative 6% rate:
| Lay price | Lay wins this often if the price is fair | Lay must win this often to break even |
|---|---|---|
| $1.70 | 41.2% | 0.70 / 1.64 = 42.7% |
| $3.00 | 66.7% | 2.00 / 2.94 = 68.0% |
| $5.50 | 81.8% | 4.50 / 5.44 = 82.7% |
| $9.00 | 88.9% | 8.00 / 8.94 = 89.5% |
| $17.00 | 94.1% | 16.00 / 16.94 = 94.5% |
Laying runners at exactly their fair price loses at every price once commission is paid. A strike rate means nothing until you know the prices: 90% at $9.00 clears break-even by half a point, and 90% at $17.00 is a loss.
100 lays at $3.00, worked through
With hypothetical prices: 100 lays of $10 each at $3.00. Every lay risks 10 x (3.00 - 1) = $20 to collect $10, which is $9.40 after an illustrative 6% commission. A $3.00 price says the runner wins one race in three.
| Lays won | Lays lost | Before commission | Commission | After commission |
|---|---|---|---|---|
| 72 | 28 | 720 - 560 = +$160 | 72 x 0.60 = $43.20 | +$116.80 |
| 70 | 30 | 700 - 600 = +$100 | 70 x 0.60 = $42.00 | +$58.00 |
| 68 | 32 | 680 - 640 = +$40 | 68 x 0.60 = $40.80 | -$0.80 |
| 67 | 33 | 670 - 660 = +$10 | 67 x 0.60 = $40.20 | -$30.20 |
| 65 | 35 | 650 - 700 = -$50 | 65 x 0.60 = $39.00 | -$89.00 |
A lay is won when the runner loses. Each lay sits in its own market, so commission is 60 cents on each winning lay (10 x 0.06), and losing lays pay none.
Note: Two lays in one race share one commission charge on the market's net result. Lay two runners for $10 each at $3.00, and if one of them wins you are down 20 - 10 = $10 and pay no commission, where two separate markets would also have charged 60 cents on the lay that won. If neither wins you collect $20 and pay 20 x 0.06 = $1.20, the same as two markets.
Each runner that wins instead of losing moves the total by $29.40: the $20 liability paid plus the $9.40 that lay would have kept. Five of them turn +$116.80 into -$30.20. The 67-winner row is the one to remember: a 67% strike rate, $10 ahead before commission and $30.20 behind after it.
If $3.00 were exactly the runners' true price, each lay would be worth (2 / 3) x 9.40 - (1 / 3) x 20 = 6.27 - 6.67 = -$0.40 on average, which is the expected commission and nothing else.
Commission and the break-even lay price
Turn the table around and ask what the runners' true price has to be for lays at $3.00 to break even:
true price needed = 1 + (lay odds - 1) / (1 - commission rate)
| Commission rate (illustrative) | True price needed | True chance at most |
|---|---|---|
| 0% | $3.00 | 33.3% |
| 4% | 1 + 2 / 0.96 = $3.08 | 32.4% |
| 6% | 1 + 2 / 0.94 = $3.13 | 32.0% |
| 8% | 1 + 2 / 0.92 = $3.17 | 31.5% |
| 10% | 1 + 2 / 0.90 = $3.22 | 31.0% |
At 6%, lays at $3.00 break even only on runners that win 32.0% of the time or less, against the 33.3% the price implies. A lay at $3.00 needs that gap of about 1.4 percentage points (1 / 3.00 - 0.94 / 2.94 = 0.3333 - 0.3197 = 0.0136) just to cover commission.
Run the other way, the break-even lay price for a runner whose true price is $3.30 is 1 + (3.30 - 1) x 0.94 = $3.16 at 6%. Lay it shorter than that and any edge comes from the price, not the act of laying, and it is an average over many lays: each $10 lay at $3.00 still pays $20 whenever the runner wins.
The exchange sets its commission in its own terms, rates can differ between markets and change over time, and the terms can add other charges for some winning customers. Treat the rate as an input and re-run the numbers when it changes. The exchange commission guide shows how commission is charged on net winnings across a market. The lay bet calculator shows that true price for any lay as its effective lay price, beside the liability and what the lay keeps, at the rate you type in.
Risk: Betting involves risk. A lay priced shorter than its break-even line has an edge only on average, the commission rate can change, and there is no guarantee of profit. See responsible gambling for limits and support.
Variance: what large liabilities do to a good record
Suppose your lays are good: you lay at $3.00 runners whose true price is $3.30, so they win 1 / 3.30 = 30.3% of the time. At 6% commission each lay is worth 0.697 x 9.40 - 0.303 x 20 = 6.55 - 6.06 = +$0.49 on average, about $49 per 100 lays.
That edge is small next to the swings. Each lay ends +$9.40 or -$20, and the number of runners that win in a sample moves around by chance. A run is behind when the runners that win, times $20, outweigh the lays won, times $9.40: at 100 lays that is 32 or more winners (68 x 9.40 - 32 x 20 = -$0.80). Counted with the binomial distribution at a 30.3% chance for each runner:
| Lays in the sample | Behind when this many runners win | Chance of finishing behind, with this edge |
|---|---|---|
| 100 | 32 or more | about 39% |
| 250 | 80 or more | about 30% |
| 500 | 160 or more | about 22% |
| 1,000 | 320 or more | about 13% |
So about two runs of 100 in five finish behind even when every lay was a good bet. Short stretches are rougher. In any 10 lays there is about a 5% chance that six or more of the runners win. Six winners out of 10 costs 4 x 9.40 - 6 x 20 = 37.60 - 120 = -$82.40.
Bigger liabilities make the swings bigger. Lay $10 at $9.00 on runners whose true price is $10.00, so they win 10% of the time, and each lay is worth 0.90 x 9.40 - 0.10 x 80 = 8.46 - 8.00 = +$0.46, almost the same edge. Each loser now costs $80, so a run of 100 is behind once 11 or more runners win (89 x 9.40 - 11 x 80 = -$43.40). The chance of finishing behind is about 42% after 100 lays, 37% after 250, 35% after 500 and 28% after 1,000, against 39%, 30%, 22% and 13% at $3.00. Variance in betting shows how wide the range gets and how to size bets for it.
Risk: Betting involves risk. An expected value is an average, not a forecast: a lay method with a real edge can finish 100 lays behind, and a losing run is a time to check the method, never to raise stakes. See responsible gambling for limits and support.
The edge comes from the price, not from laying
Every lay is matched against a back at the same price. Whatever the layer wins the backer loses, and the exchange takes commission from whoever finishes a market ahead. Backers and layers together finish behind by the commission. Laying is not a source of profit in itself: a layer's win is a backer's loss, and which side comes out ahead depends on the prices they traded at.
A lay is also a back on the rest of the field. Laying at $3.00 risks $2 to collect $1, which is backing all the other runners together at 1 + 1 / 2 = $1.50, or about $1.47 after 6% commission (1 + 0.5 x 0.94). A $1.50 bet is not a good bet because it wins two times in three, and neither is the lay.
What makes a layer profitable is what makes a backer profitable: prices that are wrong in your favour, often enough, after costs. Lay betting strategies sets out how to build that around a fair price and a liability cap, while the lay betting hub covers liability, commission and trading together.
Risk: Betting involves risk. A price that is wrong in your favour can still lose, and a lay pays its full liability every time the runner wins, so there is no guarantee of profit. See responsible gambling for limits and support.
How to test your own lays
Before you trust a lay method, measure it:
- Record every lay: date, market, price, lay stake, liability, commission and result.
- Record each runner's last price before the jump.
- Total the results after commission, never before.
- Compare your lay price with that closing price. With illustrative prices, laying at $3.00 a runner that started at $3.40 means the market moved your way: the close implied 1 / 3.40 = 29.4% against the 33.3% you laid at.
- Count enough lays. With the swings above, a few hundred is a start, not a verdict.
Closing prices give an earlier read than profit and loss, because every lay has one whether it wins or loses. Closing line value in horse racing covers the idea from the backer's side.
When laying is the wrong tool
Skip the lay when:
- the edge you expect per lay is smaller than the commission it pays on average: at 6%, $10 lays at $3.00 that win two times in three pay about 40 cents a lay;
- you cannot keep the full record the test above needs, so a lucky run and a working method would look the same;
- your record only looks good on strike rate, or only before commission;
- you are laying to win back a loss, or could not pay the liability today without topping up the account. Stop there.
Using B337's closing lines to check lays
B337 does not lay, back or trade on the exchange, so each lay in your records is one you placed yourself. Bookmaker names are trade marks of their owners. B337 is not affiliated with them.
For the testing step on racing lays, the Terminal shows closing lines, the last prices before the jump, with flucs, Betfair back and lay, and prices from 40+ bookmakers across racing and sports. That lets you set the price you laid at against where the market finished. Prices are read on a repeating cycle, so use them as a check on your records, not as a settlement figure.
Risk: Betting involves risk. Beating the closing price on some lays is not proof of a method, and past results are no guarantee of future results. See responsible gambling for limits and support.