K : Kelly Criterion
Jackpot – a tote pool bet which requires predicting the winner in a set number of races (normally six) at a meeting – if nobody predicts the winners, the pool is carried over to the next meeting. Scoop6 in the UK is a special market on Saturday racing which can produce a pool of six or seven figures .
Kelly Criterion – often considered the optimum strategy for staking which balances an edge with the chance of ruin. A simple equation where the fraction of your bank to stake, f = (bp – q) / b, where b is the decimal odds-1, p is the probability of winning and q is the probability of losing (1-p)
Lay Bet – in Betting Exchanges the odds available to oppose or take bets on a selection. Equivalent to the liability a bookmaker would take on a bet – commission is applied on any profits.
Live betting – another term for in-play betting. Often used by Continental European based bookmakers.
Lucky 15/31/63 – popular permutation bet which includes singles on each selection. A Lucky 15 is a Yankee with four singles, Lucky 31 a Canadian with five singles and a Lucky 63 a Heinz with six singles.