| # | Runner | SP | Lay @ | Stake £ | Liability £ | P&L if Wins |
|---|
When you lay a runner you act as bookmaker — collecting the stake if they lose, paying out
stake × (price − 1) if they win. Your total staked is the sum of all lay stakes:
you collect that if any runner wins, and pay out that runner's liability.
Green Up calculates stakes across all runners that lock in the same P&L regardless of who
wins. Let S = Σ(1/price_i) (the implied market book). The guaranteed profit is
total_staked × (S − 1) / S — positive when the market is underround
(book < 100%), negative when overround (book > 100%). Each runner's green stake is
total_staked / (S × price_i).