Who Compiles Greyhound Odds?
Greyhound racing odds are compiled by specialist traders employed by bookmakers, working from the race card, historical form data, and track-specific knowledge to produce a preliminary market that reflects their best estimate of each dog’s probability of winning. These individuals are typically called tissue compilers or greyhound traders, and their work on BAGS meetings is continuous throughout the working week — the volume of BAGS racing means that compilation is an ongoing daily function rather than an occasional task.
The quality and depth of greyhound trading varies considerably across the bookmaking market. The largest operators — bet365, William Hill, Ladbrokes, Coral — employ dedicated greyhound trading teams whose expertise covers the full range of GBGB-licensed venues, with specific track knowledge built through years of market observation. Smaller operators typically use a combination of in-house trading and price feeds sourced from specialist greyhound data suppliers, which aggregate form and market information from the major operators to provide a pricing reference for bookmakers without the resource to compile independently.
The Racing Post’s published tissue prices — the preliminary market estimates produced by the paper’s own analysts before bookmaker markets open — function as a widely-used reference point for traders across the industry. A bookmaker whose internal price for a specific selection differs significantly from the Racing Post tissue will typically be aware of that divergence and will have a specific reason for it: insider knowledge, a different form weighting, or a deliberate commercial positioning in the market. When the RP tissue and the bookmaker’s early price align closely, the market reflects a broad consensus on form. When they diverge significantly, that gap is analytically informative for the punter.
The Tissue Price and Early Market
The tissue price is the foundation of the greyhound odds-setting process. It is not an arbitrary starting point — it is an informed probability estimate that reflects the form evidence available at the time of compilation. The tissue compiler reads the race card, assesses each dog’s recent runs, weights the grade and distance relevance of each run, accounts for the trap draw, and converts their assessment of relative probability into a set of prices that, when expressed as implied probabilities, sum to a figure above 100 percent — the overround — that represents the intended bookmaker margin.
The typical overround on a BAGS greyhound six-runner market is 115 to 125 percent, depending on the operator and the competitive balance of the field. A tightly contested race with four or five dogs of similar form is harder to price accurately than a race with a clear ability leader, which means tightly contested races sometimes carry a slightly wider overround as the compiler hedges against pricing errors in a close field. The overround is not uniform across the field — it is typically distributed asymmetrically, with the favourite carrying a tighter margin (closer to true implied probability) and longer-priced dogs carrying a wider margin, reflecting the lower volume of bets expected on outsiders and the reduced importance of pricing precision for those runners.
When the early market opens — typically 30 to 60 minutes before a BAGS race — the tissue price becomes a published bookmaker price available to all customers. At this point the market enters its active phase: bets are placed, exchange prices respond, and the prices at different operators begin to diverge as each operator’s own book position develops. A bookmaker that has taken significant early money on a specific dog will typically shorten its price to reduce further liability. A bookmaker with little money on a specific runner may maintain its price or even lengthen it to attract volume. The early price movement across the market is, in aggregate, a real-time reflection of where money is going.
How the Overround Works Against Bettors
The overround is the mathematical mechanism by which bookmakers ensure a profit from every balanced book of bets. In a theoretically fair market on a six-runner greyhound race, the implied win probability of each dog would sum to exactly 100 percent, and a bookmaker paying out at those prices would break even on every race. The overround adds excess implied probability above 100 percent, which creates a systematic shortfall in what the market pays out relative to what a fair market would pay.
A concrete example. Suppose a bookmaker prices a six-runner race with the following implied win probabilities: Dog 1 at 28%, Dog 2 at 22%, Dog 3 at 17%, Dog 4 at 14%, Dog 5 at 11%, Dog 6 at 8%. These sum to 100% — a fair book. Now add the bookmaker’s 20% overround: each implied probability is inflated proportionally, so the six prices now imply 120% combined probability. The odds offered to bettors are correspondingly shorter than a fair market would produce. A dog with a true 28% chance of winning is priced to imply roughly 33.6% — slightly higher than its fair probability — which means the odds are shorter than they should be, and the punter is systematically underpaid on every winning bet relative to a fair market price.
The practical magnitude of the overround on a specific bet depends on the bookmaker. Major UK licensed operators vary in their standard BAGS greyhound overround from approximately 113 percent at the most competitive end to 125 percent or above at the least competitive. On a single win bet at a 120 percent overround market, the punter is, on average, receiving approximately 83 percent of what a fair market would pay on each winning bet. Over a large number of bets at a purely random selection rate, the long-run loss rate approaches 16.7 percent of total staked — the inverse of the overround minus one. Shopping for the best odds across operators consistently reduces the effective overround paid.
The overround also compounds in accumulator betting. A four-fold accumulator built from four races each priced at a 120 percent overround market effectively applies the overround four times — the multiplicative effect means the expected return on a random-selection greyhound accumulator is substantially below the expected return on an equivalent single bet. This is why the value assessment of individual legs matters more, not less, when building accumulators: the embedded margin in each leg is compounded by the multiplication, making weak legs proportionally more damaging in an accumulator than in isolation.
Market Movement in Greyhound Racing
After the early market opens, greyhound prices move continuously in response to betting volume until the race starts. The nature and speed of this movement carry information that analytical punters use to supplement their form-based assessment. A dog’s price shortening rapidly in the final 15 minutes before the off — compressing from 4/1 to 5/2 on the exchange — suggests that money with a view is arriving. It may be handler support, a track regular who has seen the dog in the paddock, or simply a large punter who has reached the same analytical conclusion from the public form. The money itself does not distinguish between these sources, but the pattern of movement is real evidence of market sentiment.
The exchange is the most transparent window into market movement for greyhound betting. The back and lay prices on Betfair Exchange update continuously, and the volume of money matched at different prices — visible in the liquidity columns — shows how much confidence is behind any given price level. A dog whose exchange price shortens from 4.0 to 3.0 while matching several hundred pounds at each price level is experiencing genuine informed buying. A price movement from 6.0 to 5.0 matched on very thin volume may be one larger-than-usual bet moving a shallow market rather than a broad consensus shift.
Drifters — dogs whose price lengthens between market open and the off — carry complementary information. A dog drifting consistently from 3/1 to 5/1 suggests that the market is finding reasons to discount it: money may be coming in on a rival, the handler community may be expressing reduced confidence, or the bookmaker may simply be moving the price to attract volume on a runner where their book is overexposed. Not all drifts are informative — thin early markets can produce price lengthening that reverses when volume arrives — but a sustained drift of a full point or more across the exchange in the final 10 minutes before the off is a data point worth factoring into any final assessment of the race.
SP Compilation Process
Market movement continues until the moment the hare starts and the traps open — at which point the market freezes and the starting price is recorded. The starting price is the official price at the moment a greyhound race begins, compiled from the prices offered by the major on-course and off-course bookmakers in the final moments before the traps open. The SP compilation methodology for GBGB-licensed greyhound racing follows an established industry process, with the compiled SP used as the settlement basis for all SP bets and as the input to the Computer Straight Forecast and Computer Tricast dividend calculations.
In practice, the SP for most BAGS races is compiled from the prices offered by the major licensed bookmakers at the point of race start, cross-checked against the exchange market price for consistency. The compilation process is not a single bookmaker’s decision — it is an aggregate of the market position of multiple operators at the moment of the off. For the punter, this means the SP represents the consensus of the market as a whole at the time the race starts, incorporating all the price movements, volume shifts, and late money that occurred between the early market and the off.
For punters taking SP rather than an early price, the compiled SP reflects the full market information available at the time of race start — which is generally more accurate than an early price, but comes with the loss of the price protection benefit. For SP bets on races where Best Odds Guaranteed is not available, the decision to take SP or early price is a pure assessment of whether the dog is more likely to shorten or drift. Early prices on dogs expected to attract handler support before the off are best taken early and held; prices on dogs likely to be unnoticed by the wider market until last-minute form readers arrive are often better at SP.
The Price Is Already the Bookmaker’s Margin
Every number on a greyhound odds board is the result of a process — form reading, probability estimation, margin application, market competition — that begins with a trader’s assessment and ends with a price that systematically understates the true probability of each runner winning by the proportion embedded in the overround. There is no neutral price. The moment the trader types in the first figure, the margin is already there.
Understanding how odds are compiled does not make them easier to beat. It does make the task of identifying when they are wrong more tractable. The tissue compiler is working from the same publicly available form data as every other punter, and they are working at speed across a large volume of BAGS races. They will sometimes get it wrong — misweighting a grade change, missing a trainer pattern, applying a generic track bias to a dog whose running style is an exception. Those errors are where the analytical punter finds the price, and knowing how the price was built is the prerequisite for recognising when the building was done with the wrong materials.