The Bookmaker's Business Model
Bookmakers don't profit by predicting football better than you. They profit by building a mathematical edge into every market they offer. This edge—the margin or "overround"—ensures they make money regardless of outcomes, as long as they balance their books reasonably well.
Understanding margins helps you identify where to find value and which bookmakers drain your edge.
Calculating the Overround
Convert odds to implied probabilities and add them together. The amount exceeding 100% is the overround.
Example: A Three-Way Market
Home: 2.20 → 45.5% implied Draw: 3.40 → 29.4% implied Away: 3.20 → 31.3% implied
Total: 106.2%
The 6.2% overround represents the bookmaker's margin. They're charging you 6.2% of the market for access to bet.
Margins Vary Significantly
Sharp bookmakers (Pinnacle, some Asian markets): 2-3% margins Competitive bookmakers: 4-6% margins Recreational bookmakers: 8-12% margins
This variation has massive implications for your bottom line.
Why Margins Matter
Impact on Expected Value
Lower margins mean higher potential returns. Consider a bet where true probability is 50%:
At a 2% margin bookmaker: You might find odds of 1.98 (50.5% implied) At a 6% margin bookmaker: You might find odds of 1.89 (52.9% implied) At a 10% margin bookmaker: You might find odds of 1.81 (55.2% implied)
Your edge on the same bet ranges from -0.5% to -5.2% depending solely on which bookmaker you use. The market being analyzed is identical—only the margin differs.
Where Margin Hides
Bookmakers apply margins unevenly:
Favorites often carry lower margins. The heavy favorite at 1.30 might be close to fair price, while the 6.00 outsider absorbs most of the overround.
Popular markets have lower margins. Premier League Match Odds might carry 3% overround at a bookmaker whose lower-league markets carry 8%.
Live betting carries higher margins. The speed and uncertainty of in-play markets allow bookmakers to charge more.
Margin Drag Over Time
Even small margin differences compound:
If you bet €1,000 total per month with 5% edge:
- At 2% margin bookmaker: Expected profit ≈ €30
- At 6% margin bookmaker: Expected profit ≈ €-10
The same selections, same analysis, same bets—but one scenario profits while the other loses. Margin is that important.
Comparing Bookmakers
Why You Need Multiple Accounts
No single bookmaker offers best odds on every market. Using multiple accounts allows you to shop for the best price on each bet.
The practice is called "line shopping" and is essential for serious bettors. Even a 2% improvement in average odds significantly affects long-term returns.
What to Look For
Margin levels: Check overall market margins, not advertised "best odds" claims.
Market depth: Do they offer the specific bets you want?
Limits: Some bookmakers allow high stakes; others restrict winning customers quickly.
Speed of odds updates: Sharp bookmakers adjust quickly. This is good if you're following their lines, problematic if you're trying to beat them.
The Sharp/Soft Distinction
"Sharp" bookmakers (Pinnacle, SBObet) offer low margins but restrict winners. They're excellent for checking true market prices but may limit your account if you win consistently.
"Soft" bookmakers offer higher margins but tolerate winners longer. They're where you might actually be able to bet your edge.
This creates a strategy: use sharp bookmakers to identify true prices, then look for soft bookmakers offering better odds than sharp lines suggest.
Margin and Value Identification
Margin Affects Value Calculations
When comparing your probability to implied probability, remember that implied probability includes margin. A bet that looks marginal against sharp odds might actually have significant edge.
Example:
- Your probability estimate: 50%
- Sharp bookmaker (2% margin): 1.96 odds (51% implied) → -1% edge
- Soft bookmaker (8% margin): 2.10 odds (47.6% implied) → +2.4% edge
The same underlying analysis produces different conclusions based on where you can bet.
Using Sharp Lines as Reference
Many professional bettors use sharp bookmaker odds as their probability reference rather than their own models. The thinking: sharp markets are efficient enough that beating them is extremely difficult.
Value then comes from finding soft bookmakers offering odds better than sharp lines—odds that exist because of higher margins and slower price adjustments.
Practical Implications
Shop every bet. Never bet at the first price you see. Check multiple bookmakers.
Maintain multiple accounts. You need options to capture best odds consistently.
Track your actual margins. Calculate the average margin you're betting into. This reveals whether you're finding value.
Consider margin in market selection. If a market consistently has 10% margins, you need 10% edge just to break even. Choose battles wisely.
Understand the business model. Bookmakers aren't charities. They've engineered their systems to extract money from bettors. Your job is to find the gaps in their engineering.
Margins are the invisible tax on every bet. Minimizing this tax through smart bookmaker selection is one of the easiest ways to improve your bottom line.