Expected value
Expected value, or EV, is the single most important concept in matched betting. It is the amount you should expect to make or lose on a bet based on the known probabilities of each outcome. Understanding it is the key to making consistent long-term profit.
How EV works
A bet has positive expected value (+EV) when the odds are better than the true probability of the outcome. A simple example: a fair coin toss has a 50/50 probability for each side. Fair odds would be 2.00. If someone offered you odds of 3.00 on a coin toss you would take it every time, because over enough tosses that edge turns into reliable profit.
Most bets placed with bookmakers have negative expected value (-EV) because bookmakers build a margin into their odds. Promos change this. When a bookmaker boosts odds or offers a conditional refund, the adjusted return can push the bet into positive EV territory.
Our goal as matched bettors is to only ever place bets with a +EV.
Value does not mean risk-free
A +EV bet can still lose. If you tossed that coin three times and lost every one you would be down $3 despite having a genuine edge. This is variance. The edge only shows up reliably over a large enough sample of bets. When we hedge by laying at Betfair we eliminate variance entirely. When we do not hedge we accept some variance in exchange for a larger potential return.
Where the value comes from
Welcome bonuses are the starting point. The most consistent long-term profits come from the following sources.
Odds boosts. A bookmaker inflates the odds on a specific outcome beyond its true probability. When the boost is large enough you can lay at Betfair and lock in a guaranteed profit. Smaller boosts may still be worth taking as unhedged value bets. Odds boosts are some of the most reliable +EV opportunities available.
Conditional refunds. A bookmaker offers a bonus bet refund if a specific condition is met, for example getting your stake back if your horse runs second or third. You cannot guarantee profit outright but the promo gives you a positive expected return over time. You can often back opposite outcomes at two different bookies on the same event to give yourself a shot at both bonuses while removing the risk. These are among the most common promos you will encounter and in the long run they are more profitable than welcome bonuses.
Early payouts. A bookmaker pays out your bet early if a certain condition is met during the event, such as your team taking a lead by a certain margin before full time. These can produce large returns but tend to be high variance. Understanding variance is important before using early payout promos regularly.
Pricing discrepancies. Bookmakers set their own odds independently and do not always agree on the true probability of an outcome. These disagreements create three types of opportunity.
- An arbitrage (arb) exists when you can back a selection at one bookmaker and lay it on Betfair (or dutch with another bookies) at odds that guarantee a profit regardless of the result.
- A middle exists when two bookmakers have priced a market so differently that you can back both sides at odds that create a window where both bets win simultaneously.
- A value bet exists when a bookmaker has simply priced a selection higher than its true probability warrants, giving you a positive expected return without needing to hedge.
We have tools designed to identify all three of these opportunities across hundreds of markets in real time.
For a full breakdown of promo strategies and how to approach each type, see the Promo Strategies course. For non-promo strategies including arbitrage and value betting, see the Non-Promo Strategies course.