Dutching
Splitting a total stake across all outcomes in proportion to their prices so every outcome returns the same amount.
To dutch two outcomes at decimal odds A and B with total stake S, stake S·(1/A)/(1/A+1/B) on the first and S·(1/B)/(1/A+1/B) on the second. If 1/A + 1/B is less than 1 the equal return exceeds S and the position is an arbitrage; if it is more than 1, dutching just spreads a losing position evenly.
Every book↔book card on ArbMonster is a dutching calculation: the two bet sizes shown are the proportional split of your sidebar stake, and the profit is the equal return minus the total staked.
Odds 2.10 and 2.05, stake $1,000: 1/2.10 = 0.476, 1/2.05 = 0.488, sum 0.964. Stake $494 and $506. Either outcome returns $1,037 — a $37 profit (3.7%).
Measured on ArbMonster: Dutching calculator
Related terms: Arbitrage · Decimal odds · Surebet