Same game multi odds are calculated from the chance that every leg lands together: the bookmaker estimates each leg, adjusts for how the legs move together, adds a margin and quotes one price. That is why an SGM usually pays less than its legs multiplied, and why it sometimes pays more.
In the worked AFL example below, legs at $1.65 and $2.10 multiply to $3.465. Allowing for how the two legs move together cuts that to $2.77, and the bookmaker's extra margin brings the price on offer down to $2.65. Same game multis explains the bet itself.
Independent legs multiply, correlated legs do not
Two results are independent when one tells you nothing about the other, such as one team winning in Adelaide and a forward kicking two goals in a different game in Perth. Then the chance of both is the two chances multiplied, and the fair price of both is the two fair prices multiplied. That is how a standard multi bet is priced, whatever sports betting markets its legs come from.
Legs in one game are usually linked, so the chance of both needs one more number, the chance of the second leg given that the first one lands:
- joint chance = chance of leg 1 x chance of leg 2 given leg 1 lands
- lift = chance of leg 2 given leg 1 lands / chance of leg 2 on its own
- fair SGM price = fair legs multiplied / lift
A lift above 1 means the legs move together (positive correlation), so the pair is worth less than its legs multiplied. Below 1 they pull apart (negative correlation) and the pair is worth more, and exactly 1 means no link at all. Correlated bets covers other ways to measure a link.
Worked: a team win plus its key forward kicking two goals
Illustrative prices for one AFL game, not a real match or a current market. Each fair chance is the implied chance divided by its market's total, for example 1 / 2.10 / 1.08225 = 44.00%:
| Leg | Bookmaker's prices | Market adds up to | Fair chance |
|---|---|---|---|
| Team A to win | Team A $1.65, Team B $2.25 | 105.05% | 57.69% |
| Team A's key forward to kick 2 or more goals | Yes $2.10, No $1.65 | 108.23% | 44.00% |
Now your estimate of the link: the forward kicks two or more in 55% of Team A's wins and 29% of its other games. That averages back to his 44%: 0.57692 x 0.55 + 0.42308 x 0.29 = 0.44.
| Price for the pair | Working | Price |
|---|---|---|
| The bookmaker's legs multiplied | 1.65 x 2.10 | $3.465 |
| Fair, if the legs were unrelated | 1 / (0.57692 x 0.44) = 1 / 0.2538 | $3.94 |
| Fair, with the link | 1 / (0.57692 x 0.55) = 1 / 0.3173 | $3.15 |
| The bookmaker's SGM price | Quoted in its builder | $2.65 |
The lift is 0.55 / 0.44 = 1.25: the pair lands 25% more often than multiplying assumes, so its fair price is 3.94 / 1.25 = $3.15. Paying the multiplied $3.465 would return 0.3173 x 3.465 = $1.10 per $1 on these chances, which is why a bookmaker will not price linked legs that way. At $2.65 the SGM returns 0.3173 x 2.65 = 84.1 cents per $1, a cost of about 15.9 cents.
Taking the $2.65 apart
Two things separate $3.465 from $2.65. First the link: 3.465 / 1.25 = $2.772, which is the SGM price at the legs' own margins (1.05051 x 1.08225 = 113.69%). Then extra margin: 2.772 / 2.65 = 1.046, about 4.6% more. Of the $0.815 gap, $0.693 is the link and $0.122 is margin. All told, the SGM's implied chance, 1 / 2.65 = 37.74%, sits about 18.9% above the fair 31.73% (37.74 / 31.73 = 1.189).
Risk: Betting involves risk. The link and the fair chances here are estimates, the pair still misses about 68 times in 100, and on these numbers the SGM costs about 15.9 cents per $1. See responsible gambling for limits and support.
How the margin grows as legs are added
An SGM has no other side to add up, so its margin cannot be read straight off the prices. A simple model shows how it builds. Say the bookmaker prices every SGM at the fair chance of all its legs landing, times each leg's market total, times the same 4.6% extra it took on the pair above for every leg after the first. On that model the average return per $1 depends only on those totals, whatever the link between the legs:
| Legs | Leg added (its market adds up to) | SGM book | Average return per $1 |
|---|---|---|---|
| 1 | Team A to win (105.05%) | 105.05% | 95.2 cents |
| 2 | Key forward 2 or more goals (108.23%) | 118.93% | 84.1 cents |
| 3 | Over the total points line, $1.90 each side (105.26%) | 130.95% | 76.4 cents |
| 4 | A midfielder to get 25 or more disposals, Yes $1.95, No $1.75 (108.42%) | 148.52% | 67.3 cents |
Working for the third row: 1.18925 x 1.05263 x 1.04604 = 1.30947, so $1 returns 1 / 1.30947 = 76.4 cents on average. Four legs keep about 32.7 cents of every dollar, against 4.8 cents on the head to head alone. The player legs come from wider markets than the match legs here, so each costs more to add, and how much extra a bookmaker loads on for each leg is its own choice. Same game multi strategy covers how many legs to use.
Negative correlation: when an SGM can price higher
Legs that pull against each other land together less often than multiplying assumes, so the fair SGM price sits above the legs multiplied. Swap the second leg for Team B's key forward to kick two or more goals, at Yes $2.30 and No $1.55: a 107.99% market and a fair chance of 40.26%. Say he kicks two or more in only 30% of Team A's wins and in 54.25% of its other games, which averages back to his 40.26%.
| Price for the pair | Working | Price |
|---|---|---|
| The bookmaker's legs multiplied | 1.65 x 2.30 | $3.795 |
| Fair, if the legs were unrelated | 1 / (0.57692 x 0.40260) = 1 / 0.23227 | $4.31 |
| Fair, with the link | 1 / (0.57692 x 0.30) = 1 / 0.17308 | $5.78 |
| An illustrative SGM price | Quoted in the builder | $4.85 |
The lift is 0.30 / 0.4026 = 0.745, below 1, so the pair is worth more than its legs multiplied: 1 / 0.17308 = $5.78. The $4.85 is 4.85 / 3.795 = 1.278 times the legs multiplied, about 28% above them, and still 16.1% below fair, so it returns 0.17308 x 4.85 = 83.9 cents per $1. A price above the legs multiplied is the link priced the other way, not a gift.
A bookmaker can also decline to price a combination at all. Under clause 4.3.2 of NSW's Bookmaker Declared Betting Events Betting Rules (checked October 2026), a bookmaker those rules cover need not take bets or quote prices on every outcome or contingency.
Risk: Betting involves risk. A price above the legs multiplied can still carry a large margin, and this pair lands only about 17 times in 100 on these estimates. See responsible gambling for limits and support.
The same SGM priced at two bookmakers
Each bookmaker sets its own leg prices and its own view of the link, so one ticket can be priced quite differently from one bookmaker to the next. The positive pair at two illustrative bookmakers, against your fair joint chance of 31.73%:
| Bookmaker A | Bookmaker B | |
|---|---|---|
| Team A to win | $1.65 | $1.70 |
| Key forward 2 or more goals | $2.10 | $2.00 |
| Legs multiplied | $3.465 | $3.40 |
| SGM price | $2.65 | $2.80 |
| SGM price / legs multiplied | 0.765 | 0.824 |
| $20 returns on a win | $53.00 | $56.00 |
| Average return per $1 | 84.1 cents | 88.8 cents |
Bookmaker B has the lower legs multiplied and the higher SGM. Either it rates the link as weaker or it takes less margin, and the prices alone cannot tell you which. You do not need to know: the same win pays $3 more. The ratio row shows how far each bookmaker cuts the multiplied legs for the link and its margin together.
Before you compare, check the tickets match leg for leg: the same player, the same threshold and the same period, since a leg settled at full time is not the same leg as one that counts extra time.
Risk: Betting involves risk. A higher SGM price pays more only when every leg wins, and the 31.73% is an estimate, not a known chance. See responsible gambling for limits and support.
Mistakes when reading SGM odds
| Mistake | What it costs, on this page's numbers | The fix |
|---|---|---|
| Judging an SGM by its gap to the legs multiplied | $2.65 is 1 - 2.65 / 3.465 = 23.5% under $3.465, but most of that gap is the link; against the fair $3.15 the cost is about 15.9 cents per $1 | Compare with your own fair price for the pair |
| Using the offered leg prices as chances | Multiplying the implied 60.61% and 47.62%, then the 1.25 lift, gives 36.08%, a "fair" $2.772, so $2.65 looks only 1 - 2.65 / 2.772 = 4.4% short when it costs 15.9 cents per $1 | Take each market's margin out first |
| Taking a price above the legs multiplied as generous | The negative pair at $4.85 is 28% above $3.795 and still returns 83.9 cents per $1 | Price the pair from its joint chance |
| Comparing the legs instead of the ticket | Bookmaker A's longer price on the forward comes with an SGM that pays $3 less on a $20 win | Price the whole SGM at each bookmaker |
Risk: Betting involves risk. Reading SGM odds well tells you what a ticket costs on average; it does not make any leg more likely to land. See responsible gambling for limits and support.
SGM Saver and the bookmaker's SGM price
B337 is software, not a bookmaker, so it sets no prices: an SGM it places goes on at the price the bookmaker quotes, link and margin included.
Its SGM Saver strategy bets only for saver or stake-back offers already on your bookmaker accounts. On a game you pick, it builds a multi for such an offer and places it once the bookmaker confirms the offer covers the ticket. You set the minimum and maximum combined odds and the most legs a multi can have, and legs you choose yourself are re-priced live when the bet goes on. Same game multi automation walks through its settings.
SGM Saver belongs to Full Automation, which is arranged with the team: its price, with any charges on top, is confirmed before you pay, and each bet placed through B337 uses credits. It places tickets at seven bookmakers on AFL, NRL, NBA and soccer games, before each game starts, and only while your own computer is on, awake, online and running B337.
Many bookmakers' terms restrict or prohibit two things SGM Saver involves, automated betting and third-party access to your account, so using it may breach them. A bookmaker can then limit your stakes, void bets or close the account, and you carry that risk. Automation can bet far more, far faster, than by hand, so put a deposit limit on every account it uses.
For free and confidential support call 1800 858 858 or visit gamblinghelponline.org.au.
Risk: Betting involves risk. A saver offer does not stop a same game multi from losing, and the bookmaker's SGM price carries its margin whether you or SGM Saver build the ticket. See responsible gambling for limits and support.