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Parimutuel markets

Pool betting: all stakes go into one pool, the operator removes a takeout $\tau$, and winners split the rest pro rata. Odds are endogenous — fixed only at close — and the operator bears no risk. The pool fractions are the market's implied probabilities. A bettor staking $w$ on winning outcome $j$ receives

Pennock's dynamic parimutuel market adds continuous price discovery: shares are priced by a cost function so early buyers profit when later buying lifts the price, combining the pool's no-operator-risk property with a live price.

Code: mechanisms/parimutuel.py · Demo: examples/sim_parimutuel.py