Politics Election winner: arbitrage calculator
- Market
- 2-way
- Typical overround
- 2%–6%
- Sample arbitrage return
- -2.22%
- Profit on every outcome
- -2.22
- Total stake
- 100.00
- Sum of implied probabilities
- 102.27%
| Leg | Odds used | Effective odds | Stake |
|---|---|---|---|
| Back Candidate A | 1.650 | 1.650 | 59.26 |
| Back Candidate B | 2.400 | 2.400 | 40.74 |
| If this wins | Legs that pay | Gross return | Commission | Net profit |
|---|---|---|---|---|
| Candidate A | Candidate A | 97.78 | 0.00 | -2.22 |
| Candidate B | Candidate B | 97.78 | 0.00 | -2.22 |
No arbitrage: -2.22% return
Election markets are two-way at most bookmakers and trade continuously on prediction markets. Settlement definitions (declared winner, inauguration) differ between venues, so read them before arbitraging across a bookmaker and a prediction market.
Market structure
Politics Election winner has 2 outcomes (
Candidate A, Candidate B). Bookmakers typically price it with an overround between 2% and
6%. For an arbitrage you need prices from at least two books whose implied probabilities, taken at the best price per outcome, add up to less than 100%.
Worked example
Two books quote 1.60 / 2.40 and 1.65 / 2.35. Taking the best price for each outcome (1.65 / 2.40) gives an implied sum of 102.27%. Arbitrage: no, return -2.22%. The calculator above is pre-filled with those best prices; the stakes for 100 in total are 59.26 / 40.74.
| Outcome | Book A | Book B | Best | Stake of 100 |
|---|---|---|---|---|
| Candidate A | 1.60 | 1.65 | 1.65 | 59.26 |
| Candidate B | 2.40 | 2.35 | 2.40 | 40.74 |
Two-way specifics
Two-way markets are the simplest to arbitrage: two prices, two stakes, one check that the implied probabilities sum below 100%. Watch for different settlement rules between books (retirements, postponements).
Frequently asked questions
How many legs does a Politics Election winner arbitrage need?
One per outcome: 2 legs covering Candidate A, Candidate B. Every outcome must be backed for the position to profit whatever happens.
How large is the overround in Politics Election winner?
Typically 2% to 6% at a single book. An arbitrage needs the best prices across books to sum below 100%, so the gap between books has to exceed the margin.
Is the worked example on this page a real arbitrage?
The sample prices give an implied sum of 102.27% at the best price per outcome (arbitrage: no). They are illustrative; live prices change constantly.
What can go wrong with an arbitrage across 2 outcomes?
A leg not being available at the assumed price, a void or push on one leg, different settlement rules between books, and stake limits that stop you placing the full amount.