An NBA same game multi (SGM) joins legs from one NBA game, such as a star's points, his team's result and the game total, on a ticket that every leg must win. Many NBA outcomes move together, so the bookmaker prices the legs as a group. A star's 30 points and his team's win are more likely together than two unrelated bets, so the NBA SGM pays less than the legs' prices multiplied.
The US name is a same game parlay. In Australia it is an SGM, part of US sports betting from Australia, and online it has to go on before tip-off under the Interactive Gambling Act (s 8A(3) and s 10B). How SGM odds are calculated covers the pricing maths in any sport, and NBA games have patterns of their own.
NBA legs that move together
Two legs are correlated when one winning changes the chance of the other. A positive correlation raises the chance of the pair, so the bookmaker shortens the SGM price. A negative one lowers it, and an SGM made of opposing legs can price above the multiplied legs, if the bookmaker allows it at all.
| Pair on one ticket | How they move | Why |
|---|---|---|
| A star's points over and his team to win | Together | When he scores heavily his team tends to win, and his points are part of the margin |
| A star's points over and his team's total over | Together | His points are part of the team total |
| A point guard's assists over and a teammate's points over | Together | The NBA counts an assist only on a pass that leads directly to a made basket |
| The game total over and players' points overs on both teams | Together | A fast game gives every player more possessions |
| The game total under and a big man's rebounds over | Can move together | Rebounds come only from missed shots, and a cold shooting night leaves more of them |
| A big favourite's line and its starters' overs | Pull apart late | A big lead sends the starters to the bench |
| The underdog to win and the favourite's star over | Pull apart | A big night from the favourite's best player makes the upset less likely |
The assists row comes straight from the NBA's stat glossary, which defines an assist as a pass that leads directly to a made basket. Every assist on the ticket is also a basket for somebody else.
The blowout problem
A blowout splits two legs that look as if they belong together. A favourite at -12.5 on the line and its star's 30+ points both seem to need the favourite playing well. But once a lead gets big, coaches often take their starters off for the rest of the game. That is a coaching choice rather than a rule, so the minutes vary from team to team.
With an illustrative star who scores 0.90 points a minute:
| Game script | Minutes | Projected points | 30+ leg |
|---|---|---|---|
| Close game, plays the fourth quarter | 35 | 0.90 x 35 = 31.5 | Above 30 |
| Blowout, sits most of the fourth quarter | 27 | 0.90 x 27 = 24.3 | Well short |
The line leg wants the blowout and the points leg wants the close game. Pairing them asks for a big win in which the star kept scoring anyway, which is a narrower result than either leg alone suggests.
Minutes: the hidden leg on every ticket
Every player leg assumes minutes, and three things cut them:
- Rest decisions, most of all on the second night of a back-to-back, when a team can sit a player or limit his time.
- Blowouts, as above, which take starters off the court late.
- Foul trouble and in-game injuries, which nobody can price exactly before tip-off.
So two legs on one player are really three bets: the two counts and the minutes behind them. If his minutes fall short, both legs fall short together, and a ticket built around one player rises and falls on a single team-news decision. NBA player props shows how minutes set a prop line in the first place.
Worked example: a star's 30+ points with his team's win
Illustrative prices for one game, not a live market:
| Leg or ticket | Price | Implied chance (1 / price) |
|---|---|---|
| Team A to win (head to head) | $1.60 | 62.5% |
| Team A's star to score 30+ | $2.80 | 35.7% |
| Both legs multiplied | 1.60 x 2.80 = $4.48 | 22.3% |
| The bookmaker's SGM price | $3.70 | 27.0% |
Now your own estimate, also illustrative. Team A wins 60% of the time, the star scores 30+ 34% of the time, and when he does, Team A wins 72% of those games:
- Joint chance = 0.34 x 0.72 = 0.2448, so a fair price of 1 / 0.2448 = $4.08.
- If the legs were unrelated, the joint chance would be 0.60 x 0.34 = 0.204, a fair price of $4.90.
- Split the other way, the star scores 30+ in 0.2448 / 0.60 = 40.8% of Team A's wins and (0.34 - 0.2448) / 0.40 = 23.8% of its losses.
At $3.70, the return per $1 is 0.2448 x 3.70 = 0.906, so on your numbers the ticket costs about 9.4c per $1. A bookmaker paying the multiplied $4.48 would be paying out 0.2448 x 4.48 = 1.097 per $1 on these numbers, which is why correlated legs are priced as one bet rather than multiplied.
Judge an SGM against your own estimate of the joint chance, not against the legs multiplied, and compare the same ticket across bookmakers, because each prices the correlation its own way. The correlated bets guide covers how to spot a correlation the price misses.
Risk: Betting involves risk. The joint chance in this example is an estimate, an SGM priced above it can still lose, and every extra leg is one more way for the ticket to fail. See responsible gambling for limits and support.
Overtime and period legs on one ticket
Under the common rule type, full-game legs include overtime: head to head, the line, the total and player props all settle on the final numbers. Legs on a single period, or on the three-way result at the end of regulation time, finish earlier, and one ticket can hold both kinds.
Take a ticket with Team A to win, the game total over and Team A first half -2.5, in a game tied after four quarters. Overtime decides the first leg, can only add points to the second, and cannot touch the third, which was settled at half time. Each NBA overtime period is five minutes under Rule 5 of the NBA's playing rules, so a tied game hands every full-game leg at least five more minutes of play. Does overtime count in NBA betting sets out which markets include it.
Void legs: ruled out before tip-off, or injured during the game
A player can be ruled out after you build the ticket, and NBA final calls can come in the hours before tip-off, which is the Australian morning or early afternoon. Settlement follows your bookmaker's terms, and three rule types are common:
- The void leg is removed and the SGM is re-priced on the legs left.
- The whole SGM is void and the stake returned.
- The leg stands and loses because the bet was all-in, and the ticket loses with it. This is the NSW default: the Bookmaker Declared Betting Events Betting Rules, which bind bookmakers authorised there to take sports bets, make a bet all-in unless you agree another basis or the bookmaker's terms state one (clause 5.1.1). A multi with a losing leg is lost (clause 5.1.9).
A re-priced ticket need not pay the original price divided by the missing leg's price, because the correlation between the remaining legs is priced again. Same game multi rules works through a recalculation.
A player who starts and then leaves injured is a different case. Under one common rule type he has taken the court, so his legs stand and settle on the numbers he recorded. A star who leaves after nine minutes with six points loses a 30+ leg, and with it the ticket.
Note: Read the void clause before you build around a player listed as Questionable. The difference between a void leg and a losing leg is the whole stake.
Mistakes that make an NBA SGM cost more
- Judging the price against the legs multiplied. In the example, $3.70 looks like a poor deal against $4.48, but the useful comparison is with your joint chance of 0.2448 (a fair $4.08), at which the ticket costs about 9.4c per $1.
- Adding legs for a bigger price. Each leg carries its own margin and one more way to lose; same game multi strategy compares short and long tickets.
- Pairing a big line with the starters' overs, as in the blowout table.
- Building around a Questionable player before his status is final.
- Forgetting that full-game legs and period legs settle on different parts of the game.
Skip the SGM when the legs you like are unrelated or pull apart. Two separate bets keep each price whole and let one win when the other loses.
Where SGM Saver fits
Some bookmakers issue saver or stake-back offers on same game multis. B337's SGM Saver builds and places same game multis, NBA included, for those offers when they are already on your own bookmaker accounts, on the games you pick. It works at seven bookmakers and on four sports: AFL, NRL, NBA and soccer. SGM Saver places a multi only once the bookmaker has confirmed that the offer covers it. You set the games, the minimum and maximum combined odds, the most legs one multi can have and the player markets it may use. Bets go on before the game starts, and only while B337 runs on your computer, which has to stay on, awake and online. Valuing an offer of that kind is covered in same game multi promotions.
SGM Saver needs Full Automation. The team sets it up and confirms the price before you pay, with any charges on top of the plan spelled out, and bets placed through B337 use credits, a per-bet usage charge. The SGM Saver page lists the bookmakers and controls. 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. Many bookmakers restrict or prohibit automated betting in their terms, and a bookmaker can limit your stakes, void bets or close your account. Automation can bet far more, far faster, than by hand, so set a deposit limit with each bookmaker. There is no guarantee of profit. See responsible gambling for limits and support.