Vig in Sports Betting: The Hidden Tax in Every Bet

Every bet you place carries a structural tax baked into the line. Here's what it costs you, and which books charge the most.

GhostLeg, 2026-06-28, 8 min

The reason your $100 bet only wins $91 isn't bad luck. It's structural.

Every time you place a bet at a retail sportsbook, you pay a tax that never shows up on your receipt. Vig in sports betting is baked silently into every line, on every game, across every sport you bet. The industry calls it the vig (short for vigorish). You've probably also heard it called the juice, the hold, or the overround. They're all the same thing: the cut the house takes before the contest even starts.

Most bettors know the vig exists in a vague, abstract way. What they don't know is exactly how much they're paying, or that the difference between books isn't a rounding error. It's real money, and it compounds over hundreds of bets.

GhostLeg logs the implied probability of every line we track. Across a recent 30-day sample, covering six major sportsbooks and five sports, we computed the average overround on every moneyline market in our feed. The results are worth looking at before you place another bet.

What Vig in Sports Betting Actually Means

Start with a coin flip. The true probability of heads is 50%. In a fair bet, you'd get +100 on each side: bet $100 to win $100. Even money.

But a sportsbook won't offer you +100/+100. They'll post -110/-110. You have to risk $110 to win $100 on either side. If they take $110 on heads and $110 on tails, they collect $220 and pay out $210. That $10 difference works out to roughly 4.5% of handle: that's the vig.

The math behind it: at -110, your implied probability is 110 / (110 + 100) = 52.38%. Two sides of the same market add up to 104.76%, which is more than 100%. The excess is the overround. The overround is the vig, expressed as a percentage of implied probability.

This is why understanding odds vs probability is foundational before you can even think about devigging a line. The vig hides inside the implied probability math. If you can't convert odds to probability, you can't see the tax you're paying.

The calculation for any two-way market:

Overround = (Implied Prob Side A + Implied Prob Side B) − 1

Where implied prob for negative odds = |odds| / (|odds| + 100) And implied prob for positive odds = 100 / (odds + 100)

For a three-way market (like EPL or MLS, where a draw is a real outcome):

Overround = (Home Prob + Draw Prob + Away Prob) − 1

The overround as a percentage is that number times 100. That's the book's built-in edge on the market.

What Our Odds Feed Shows: Real Book Hold Data

Here's where it gets concrete. GhostLeg tracks moneyline odds from six sportsbooks across NBA, MLB, NHL, EPL, MLS, and UFC. We computed the average overround per book per sport across all h2h markets over the last 30 days, filtering to games with at least 10 qualifying samples per combination.

The full breakdown, sorted lowest to highest vig within each sport:

Source: GhostLeg odds feed, h2h moneyline markets, 30-day sample. Sample sizes: NBA n=55, MLB n=421–427, NHL n=50–55, EPL n=47–49, MLS n=89, UFC n=57–90 per book. Data available via the GhostLeg Data API.

A few observations that stand out.

Pinnacle is in a different league. At 2.47% overall, Pinnacle's average hold is nearly half what the US retail books charge. On MLB moneylines specifically, Pinnacle averages just 2.02%, the sharpest pricing we track by a significant margin. This is by design: Pinnacle's business model is built for high-volume sharp action. They win on volume, not margin, which means they offer the closest thing to "true" odds in our feed.

The retail tier clusters between 4.5% and 5.1%. FanDuel, Bovada, Fanatics, DraftKings, and BetMGM all land in a tight band. There's no dramatic winner among the US retail apps; they all charge roughly 4–5% on two-way markets.

Soccer carries the highest vig. MLS and EPL overrounds are consistently higher than two-way sports. That's partly structural: three-way markets (home / draw / away) give books more pricing room, and the three-outcome model means the overround accumulates across three legs instead of two. MLS at DraftKings averaged 8.14%, the highest single cell in our data.

The spread across books within a sport matters. On NBA moneylines, you're paying 2.79% at Pinnacle vs 4.55% at BetMGM. That 1.76-percentage-point gap is real money compounded over a season. Over 100 NBA bets at $110 each, the expected cost difference between Pinnacle and BetMGM works out to roughly $93: nearly a full bet's worth of value recovered just by choosing the lower-vig book.

You can track current line pricing, book-by-book overrounds, and market-level hold in the GhostLeg intel dashboard. The underlying data is available for programmatic access through our Data API; book hold is one of the flagship metrics in the market intel endpoints.

How Vig Compounds Over Time

A single 4.5% vig sounds modest. Against time, it's not.

At -110, you need to win 52.38% of your bets just to break even (not 50%). At -115 (which maps to roughly 5.35% vig), you need to win 53.49%. At -120, it's 54.55%.

That delta is the amount of edge you need to find before you even start making money. Vig isn't a fee layered on top of your bets; it's a handicap built into every single market before you even form an opinion.

For parlays, it compounds. A two-leg parlay at -110/-110 carries a combined vig of roughly 9%. Add a third leg and you're at ~13%. This is one of the structural reasons books love parlays, which is why understanding parlay math (or the deeper breakdown in what does parlay mean in betting) should come before building multi-leg tickets. Every leg you add multiplies the vig stack along with the potential payout.

Same-game parlays (SGPs) are even more exposed because books price correlations conservatively. The vig per SGP leg is typically higher than on a standalone moneyline, and the book's edge widens further when outcomes within the same game are correlated.

The vig is also the structural reason that closing line value matters as a performance metric. If you're consistently beating the closing line, it means you're regularly getting prices before the book has fully balanced its exposure, getting odds that reflect less vig than the closing number. CLV positive bettors are, in a meaningful sense, partially escaping the tax.

How to Devig a Line

"Devigging" is the process of removing the book's overround to find the implied true probability of each outcome.

Start with a -115/+105 line pair.

• Implied prob of -115 side: 115 / (115 + 100) = 53.49%
• Implied prob of +105 side: 100 / (105 + 100) = 48.78%
• Total: 53.49% + 48.78% = 102.27%
• Overround: 2.27%

To devig, normalize each side by dividing by the total:

• True prob of -115 side: 53.49% / 102.27% = 52.31%
• True prob of +105 side: 48.78% / 102.27% = 47.69%

Now you have a market-implied probability stripped of the house edge. What the market actually thinks, at the price it would charge in a frictionless world.

This matters most when you're comparing across books or against a reference price. Pinnacle is often used as the devig reference because how sportsbooks set odds shows that Pinnacle's lines are among the sharpest in the world, with their overround low enough that implied probabilities sit close to true market consensus. If you devig Pinnacle's line and compare it to FanDuel's posted price, you can see whether FanDuel is offering you a discount or a premium. That gap is the starting point for any real edge analysis.

The full mechanics of odds-to-probability conversion are covered in our odds vs probability explainer: required reading before you try to apply devig math in practice.

What Our Signals Show

GhostLeg's edge detection is built on top of this exact framework. Every line we track gets devigged against our reference books before any signal fires. A "positive EV" flag in the intel dashboard, powered by the same expected value betting formula that drives professional bankrolls, means the devigged probability is meaningfully higher than what the target book is implying at their posted price, accounting for the vig on both sides.

In practice: if Pinnacle implies a 54% true win probability on an NBA moneyline, and FanDuel is posting that same side at -105 (implied: 51.2%), that's a positive expected value opportunity. The book is charging you a price that doesn't match what the sharpest market in the world thinks. Our model tracks these divergences in real time, across the books in our feed, for every sport we cover.

The book-level hold data we showed above is the floor math. It's what you're paying just to participate, before any edge analysis. Signals are how you find the spots where the retail book's line hasn't caught up to where the sharp market is priced. You can pull both (hold data and signal output) through the GhostLeg Data API.

Prediction Markets: The Low-Vig Alternative

One of the more interesting data points in the broader vig conversation: prediction markets operate at a fraction of sportsbook hold.

On Kalshi vs Polymarket: the two largest prediction markets for sports events, the effective spread between buy and sell prices typically translates to 1–2% equivalent vig on liquid markets. Compare that to the 4.5–5.0% baseline at US retail sportsbooks. The structural advantage for prediction market participants is real: you're starting each wager 2.5–3 percentage points closer to break-even.

The catch: sports market liquidity on prediction platforms is still developing. You're not going to find the depth on Kalshi that you'll find at DraftKings for NBA playoffs. But for certain events (political, economic, news-driven), prediction markets represent a genuinely lower-vig alternative to the retail sportsbook ecosystem.

This is one of the most important cross-pillar dynamics in the modern betting landscape: the same underlying probability can be expressed at ~1.5% vig on a prediction market or ~5% vig at a retail book. Understanding that difference starts with understanding what vig is in the first place.

Which Book Should You Use?

The data makes this clear in one direction. If you have access to Pinnacle (or similar sharp offshore books), the 2–3% vig discount is a structural edge you're giving up at every retail book.

For most US bettors, Pinnacle access is limited. In that case, the retail books are close enough to each other that book choice matters less than line shopping. A half-point or 5 cents of juice saved by comparing DraftKings vs FanDuel on any given game is real money over a season of bets. Line shopping across multiple books (looking at the same event across FanDuel, DraftKings, BetMGM, and Fanatics) won't beat Pinnacle's structural vig advantage, but it can recover a point or two of the gap on individual wagers.

Track current lines, compare implied probabilities across the books we feed, and flag the best available price through the GhostLeg intel feed. The overround math runs automatically on every h2h market we ingest. The data is there; the question is whether you're looking at it before placing your bet or after.

For entertainment purposes only. Past performance does not indicate future results.