Best odds guaranteed (BOG)
Best odds guaranteed is a racing concession that pays the larger of your taken price and the starting price if it drifts in your favour.
The concession is each bookmaker's own, mainly on horse and greyhound racing, and each sets its terms: which races qualify, whether each-way bets are covered, the time from which it applies and any cap on the extra paid. It can also be withdrawn from an individual account.
For a matched bettor, BOG is upside on top of an ordinary qualifying bet, sized as back stake × back odds ÷ (lay odds − commission). Back a horse for 10 units at 4.0 and lay it at 4.2 at 2% commission (use your own rate), and the lay stake is 10 × 4.0 ÷ 4.18 = 9.57 units. The pair costs 0.62 units whichever way the race goes.
If the horse wins and its SP is 7.0, BOG pays the back bet at 7.0, 60 units profit where the fixed price paid 30. The lay loses what it would have lost anyway, so the pair ends 29.38 units up. If the horse loses, or wins at an SP no bigger than 4.0, the result is the 0.62 loss.
In the OddsRelay feed
In the feed, BOG is its own feed type, GET /v2/odds/bog. The sample reply in the API reference shows the shape: sport_key horse_racing, venue set to the course, a market with key win, back[] listing bookmakers best price first and lay listing exchange offers lowest price first, each with exchange, price, available and link. It serves decimal or, with oddsFormat=american, American odds.
GET /v2/coverage lists which bookmakers and sports have rows on each product, bog included, so a tool can see whose prices a BOG table will hold before asking for it. The bookmakers filter then narrows a request to the bookmakers a user holds accounts with.
The SP itself is not in the feed. It is set at the off, after the pre-match prices the feed carries, so a tool plans on back[].price and lay[].price and the uplift is paid later by the bookmaker under its own terms.
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