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Trading floor · 8/8Betting Board
Desk · back the wrong prices Expected 0.000 · realised 0.00
Odds board · two dice · stake 1 on each line you back
The roll
Desk · two-bookmaker arbitrage
Briefing · Trading floor

Betting Board

Skill: implied probability, overround, arbitrageFirm echo: Optiver betting round

A board quotes decimal odds on outcomes of a two-dice roll. Decimal odds d pay d per 1 staked (stake included), so the implied probability is 1/d. Back a line only when your true probability beats it.

EV per 1 staked = p · d − 1 implied p = 1/d overround = Σ 1/d − 1
Shorthand
  • Two dice sums: ways = 6 − |7 − s|. 7 has 6 ways of 36; 2 and 12 have 1.
  • Σ 1/d < 1 across all outcomes → arbitrage. Stake on each in proportion to 1/d.
  • Back if d > 1/p. A 1-in-6 event needs odds above 6.0.
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