Correlated Bets and Same-Game Exposure in 2026: Why Same-Game Parlays Don't Multiply

The quick answer

• Correlation: bets on the same game or player can depend on the same outcome, so they tend to win and lose together.

• Exposure: two $100 even-money bets on a team's moneyline and the game Over, at a correlation of 0.20, swing $155 per standard deviation instead of $141.

• Fair parlay price: with each leg a fair 50% and a 30% chance both hit, the fair two-leg price is +233. Multiplying the legs gives +300.

• Sportsbooks: DraftKings' house rules void standard parlays with correlated legs, FanDuel's terms don't permit them, and both sell them through same-game parlay products instead.

• Prediction markets: Kalshi and Novig price combos through a request for quote, where other participants quote the combined contract as a contract of its own.

• Novig's parlay fee: 0.10 x P x (1 - P) per contract, already inside the quoted price. Novig's own table lists a 30% parlay at about 32.1% all-in. At a true 30%, that's an expected cost of $6.54 per $100, against $10 on a same-game parlay paid at +200.

Two bets on the same game often depend on the same outcome. The correlation between them raises the size of your worst outcome, and it's why a same-game parlay can't be priced by multiplying the legs, since the product assumes independence and misstates the chance they all hit.

What correlated bets are

Two bets are correlated when the result of one changes the chances of the other. A quarterback's passing yards and the game total going Over move together, the example Caesars uses in its same-game parlay guide.

For two win-or-lose bets, the correlation is (P(both win) - pA x pB) / √(pA(1 - pA) x pB(1 - pB)). If each bet is a 50% shot and they hit together 30% of the time, that's (0.30 - 0.25) / 0.25 = 0.20.

How we checked

The worked examples use illustrative numbers: fair 50% legs and an assumed 30% chance that both hit. The 30% is assumed for illustration and doesn't describe any measured matchup. Platform rules come from each operator's own house rules, terms, rulebook or help pages, listed under Sources and retrieved on 7 October 2026, except FanDuel's terms, retrieved on 6 October 2026.

How correlation changes total exposure

Say you bet $100 on the home team's moneyline and $100 on the game Over, each at even money with a fair 50% chance. The table lists the four ways the game can finish.

The expected result is $0 either way. The correlated pair loses the full $200 30% of the time instead of 25%, and its standard deviation is $154.92 against $141.42 for two independent bets.

The general rule is that the variance of a sum is each bet's variance plus twice their covariance. Positive correlation adds to the swing, while independent bets don't add anything extra. Five bets on one game that lean the same way can all lose on the same result, so their worst case is the sum of all five stakes.

How sportsbooks price same-game parlays

A standard parlay multiplies the legs' decimal prices. Two legs at -110 are 1.9091 x 1.9091 = 3.6446, or about +264.

That math assumes the legs don't affect each other. With the 30% joint chance above, a two-leg parlay paid at 3.6446 returns 0.30 x 3.6446 - 1 = +9.3% on average. The same price on two independent legs returns 0.25 x 3.6446 - 1 = -8.9%. A book that multiplied correlated legs would be offering a +9.3% bet.

• DraftKings: its Massachusetts house rules list among the bets that will be voided, outside of Progressive Parlays and Same Game Parlays, "any Parlay bet that includes two or more Selections where the outcomes of the Selections are correlated, regardless of the odds of such Selections."

• FanDuel: its terms don't allow parlays whose selections affect each other's outcome or pricing, unless FanDuel offers them itself, as with its Same Game Parlay.

• Caesars: its guide says it "uses its own pricing mode, to calculate an SGP's combined odds instead of multiplying each leg's individual odds." On its $10 three-leg example, positively correlated legs pay $46 to $58 against about $70 for independent legs.

The correlated legs should pay less, because they're more likely to hit together. With 50% legs and a 30% joint chance, the fair two-leg price is 1 / 0.30 = 3.333, or +233. Sportsbooks don't publish what they charge on top of that fair price. At +200, the pair would cost 0.30 x 3.00 - 1 = -10% of stake on average, against -4.55% on a single -110 straight bet.

How prediction markets price combos

Kalshi's Market FAQs say "Combos use a Request For Quote (RFQ) process": you submit a request, other participants quote prices, and when you accept, "your combo becomes part of its own order book." If a leg settles at something other than $1 or $0, the combo pays the product of the leg values.

Novig operates as Ludlow Exchange, LLC, whose rulebook defines a Combination Contract as "a standalone Contract whose payout depends on the joint resolution of two or more Legs." A parlay starts as an RFQ. Quoting members get three seconds to respond, the requester gets up to 30 seconds to accept a pre-event quote (10 seconds live), and then a one-second window opens in which any member with API access can post a better price before the order fills against the best interest available. Ludlow can reject a requested combination that "cannot be reliably or deterministically settled."

The correlation is priced by whoever quotes, in competition, and you'll see the quote before you accept it. Novig's fee page says "Parlays are priced by quote" and puts the fee at 0.10 x P x (1 - P) per contract, "already included in the quoted price." On a parlay with a fair price of 30c, the fee is 0.10 x 0.30 x 0.70 = 2.1c, and the page's own table lists that parlay at about 32.10% all-in. If 30% is the true chance, a $100 stake at 32.1c has an expected cost of $6.54. A same-game parlay on the same pair would need to pay +212 or longer to cost less.

ProphetX's parlay rules say that if a parlay holds several selections from the same event and any one is void, "the entire parlay will be void regardless of the outcomes of the other selections."

Exposure limits across open positions

Bet sizing is what you put on one bet given its edge; exposure is what you'd lose across everything open if one game went against you.

Group open positions by game and add up the worst case. With a $10,000 bankroll and $100 bets, the moneyline-and-Over pair above loses $200 in its worst case, 2% of the bankroll. Add a $100 Over on the quarterback's passing yards and the worst case becomes $300, because a low-scoring home loss can sink all three. A same-game parlay on the same legs puts that stake on the same outcome too.

Set a per-game cap in advance, written as a share of bankroll, so a cluster of small correlated bets can't add up to one large unplanned bet.

What to look for

• Shared outcomes: before placing a second bet on a game, check whether the first bet's result changes its chances.

• Worst case per game: add up every open position on the same game, parlays included, and compare it with a cap you set in advance.

• Parlay price: compare a same-game parlay quote with your own estimate of the joint chance, since multiplying the legs overstates the fair payout on positively correlated legs.

• House rules: check whether your book voids correlated legs placed outside its same-game product.

• Settlement: read the void rules for same-event combos, since at ProphetX one void leg voids the whole parlay.

• Fees: on a prediction market, check whether the parlay fee is added at checkout or already inside the quote, and whether competing participants quote the combo.

Correlated bets FAQ

Why won't a sportsbook let me parlay correlated bets?

Multiplying correlated legs would overpay the bettor. DraftKings' house rules void correlated parlays outside its Same Game Parlay and Progressive Parlay products, and FanDuel's terms don't permit them unless offered as a same-game parlay.

Why does a same-game parlay pay less than the regular parlay odds?

Positively correlated legs hit together more often than independent ones, so the fair payout is lower. Caesars says positively correlated same-game parlays "can pay less than multiplying" the individual odds.

How are parlay fees charged on prediction markets?

It varies by venue, so check whether the fee is added at checkout or already inside the quote. Novig's parlay fee is 0.10 x P x (1 - P) per contract, built into the quoted price, so a parlay with a fair price of 30c is quoted at about 32.1c all-in.

What happens to a same-game parlay if one leg is void?

ProphetX voids the whole parlay if any same-event selection is void. DraftKings drops the void leg and reprices the rest at the odds available when the parlay was placed.

Sources

Retrieved 7 October 2026, except the FanDuel terms (6 October 2026).

DraftKings Massachusetts Sportsbook House Rules, implementation date 26 August 2025: voiding of correlated parlays (section on voided bets) and Same Game Parlay settlement

FanDuel Sportsbook Terms and Conditions (New Jersey), "Parlays, Round Robins and Teasers"

Caesars Sportsbook, "Same Game Parlay" betting guide

Kalshi Help Center, "Market FAQs" (combos, RFQ and settlement)

ProphetX Help Center, "ProphetX Parlay Rules"

Ludlow Exchange, LLC, Rulebook version 1.3 (definition of Combination Contract; Rules 2.16(g) and 5.2(e) to 5.2(k))

Novig fee schedule: support.novig.com/en/articles/16195057-fees-on-novig