What Is the Starting Price (SP)?
The Starting Price is the official price at which a horse is returned at the moment a race begins — and the price at which millions of bets are settled every year. For many bettors it is simply what their bet was settled at. But understanding exactly how the SP is determined, what drives it, why it carries a built-in margin, how Betfair SP differs, and when taking SP is smart versus when it costs you money is the difference between passive and informed horse racing betting.
What Is the Starting Price?
The Starting Price (SP) is the official price returned for each horse in a race at the moment the race begins. It is determined by the prices displayed on on-course bookmakers' boards at the off and is the price at which bets struck "at SP" are settled.
SP is one of the oldest institutions in British horse racing — a standardised mechanism for settling bets that predates online betting by over a century. Before fixed-price online betting became the norm, the vast majority of horse racing bets were placed without a price being agreed — "I'll have a tenner on Arkle, SP" — with settlement depending entirely on the official price returned when the race started.
Today, SP-settled bets remain extremely common — particularly through telephone betting accounts, on-course betting with racecourse Tote facilities, and bets placed on races where fixed prices aren't available. Many online bettors also choose SP deliberately for specific strategic reasons, which this guide explores in full.
Price Unknown Until the Off
When you place a bet "at SP" you are accepting whatever the official returned price is at the moment the race starts. You don't know what price you'll receive when you place the bet — you find out when the race begins. The SP could be shorter or longer than the morning price depending on how the market moves before the off.
Price Locked In at Placement
When you take a fixed price — the morning early price or any price displayed on a bookmaker's website before the off — that price is locked in regardless of how the market subsequently moves. If the horse shortens from 6/1 to 3/1, you still get 6/1. If it drifts to 10/1, you still get 6/1. The price is certain from the moment you place the bet.
How the SP Is Determined
The SP determination process is regulated by the British Horseracing Authority (BHA) and carried out by trained SP reporters at every British racecourse. It follows a standardised methodology designed to produce a consistent, representative price for each horse.
At the moment the starting stalls open (flat racing) or the starter sends the field away (jump racing), SP reporters stationed in the betting ring note the prices displayed on the boards of on-course bookmakers. They survey a representative sample of bookmakers — the exact number surveyed depends on the size of the meeting and the number of bookmakers operating — to capture the breadth of market prices at that precise moment.
📊 SP is a snapshot of on-course bookmaker boards at the offFrom the surveyed prices, the median (middle value) is identified for each horse. Using the median rather than the mean prevents a single outlier bookmaker offering an unusually long or short price from distorting the SP significantly. If most bookmakers have a horse at 5/1 but one has it at 10/1, the median reflects the consensus price — not the outlier.
The SP reporters verify that the combined implied probabilities of all horses' SPs fall within an acceptable overround range. If the raw median prices produce an overround significantly outside the norm, adjustments may be made to individual horses' SPs to bring the market into acceptable balance. This step ensures the SP market behaves like a coherent bookmaker market rather than a collection of independently set prices.
📊 SP overround is typically 15–25% at standard UK meetingsWithin minutes of the race ending, the official SPs for every horse are published — via the BHA's data feed, Racing Post, and bookmaker settlement systems. Bets struck at SP are settled at these officially returned prices. The SP is final and cannot be amended after publication except in cases of official inquiry that affects the result itself.
✅ SP published within minutes of the race finishingThe SP reflects the on-course betting ring at a specific racecourse — not the aggregate of all off-course bookmaker prices, Betfair or any other venue. For major meetings with large betting rings (Cheltenham, Ascot, Newmarket), the SP is a highly liquid and well-informed price. For smaller provincial meetings with few on-course bookmakers, the SP can be less representative of the true market. This is one reason why Betfair SP is often considered more accurate, particularly on smaller meetings.
The SP Overround — SP Is Not a Fair Price
One of the most important facts about the SP that many bettors overlook: the SP carries a significant bookmaker margin. Taking SP on every bet is not taking a fair market price — it is accepting a margin that costs you money over time.
The combined implied probabilities of all horses' SPs in a typical UK race sum to 115–125% — meaning the SP market has a bookmaker margin of 15–25%. This is significantly higher than the 5–8% overround available on competitive bookmaker match-odds markets, and far higher than the effective 2–5% margin on Betfair's exchange. A bettor settling all bets at SP is accepting a much larger margin than one who takes fixed prices or uses the exchange.
Why Is the SP Overround So High?
On-Course Bookmakers Set Their Own Prices
Each on-course bookmaker sets their individual prices independently — their primary objective is managing their own liability book, not offering the most competitive prices in the market. Without the direct competition between dozens of online bookmakers that drives margins down in internet betting markets, on-course prices naturally carry wider margins.
Many Runners = Compounded Margin
In a 20-runner handicap, even a modest 1% margin per runner compounds across the full field to produce a substantial total overround. The SP overround is broadly proportional to the number of runners in the race — large fields produce higher total overrounds than small fields, even at similar per-runner margin rates.
The SP Captures the Least Competitive Prices
The SP is a median of on-course prices — not the best available price across the full market. Off-course competition between Bet365, William Hill, Coral, Betfair and others drives prices upward. The SP reflects only on-course prices and misses the competitive upward pressure that makes online fixed prices superior for most horses.
SP Overround — A Practical Example
A 10-runner handicap. Adding up the implied probability of each horse's SP — 1 ÷ SP for each runner — produces a total of approximately 1.20 (120%). The "true" probabilities should sum to 1.00 (100%). The 20% excess is the SP overround — the collective margin embedded in the SP prices.
What a 20% SP Overround Costs
For every £100 staked at SP on a race with a 20% overround, the expected return is approximately £83.33 — a loss of £16.67. Compared to a competitive online market with a 5% overround, which would return approximately £95.24, the SP bettor pays an extra £11.91 in margin per £100 staked.
SP vs Best Online Price Over a Year
A bettor placing 500 bets of £20 (£10,000 total staked) at SP with a 20% overround expects to return £8,333 — losing £1,667. The same bettor always taking the best available online price (5% overround) expects to return £9,524 — losing £476. The difference: £1,191 per year from margin alone, before any skill component.
SP vs Early Prices — Which Is Better?
The question of whether to take an early fixed price or accept SP depends on how the horse is likely to be bet before the race. Understanding the typical patterns of price movement makes this decision straightforward for most horses.
Horses That Typically Shorten
Well-fancied horses, stable favourites and horses with recent strong form typically shorten from their morning price to the SP as money comes in through the day. For these horses, taking the early price is almost always better — you lock in the longer morning odds before the shortening occurs. A horse at 4/1 early that goes off at 2/1 SP: early price is twice as valuable.
Horses That Typically Drift
Horses without strong market support, stable outsiders and those whose form is less fashionable often drift from their morning price to the SP. For these horses, waiting for SP — or taking a later price — can produce a better return. A horse at 8/1 early that drifts to 14/1 SP: SP is significantly better. The challenge is predicting which horses will drift before the market moves.
Horses With Stable Prices
Some horses — particularly consistent performers in competitive markets — hold their price from morning to SP with minimal movement. For these, the difference between early price and SP is small. The early price is still marginally preferable given the smaller overround of online fixed markets vs on-course SP — but the practical difference is limited.
Across the full population of horse racing bets, taking the best available early fixed price at a competitive online bookmaker consistently outperforms SP betting — because the online fixed-price overround is lower than SP, and the majority of fancied horses shorten from early price to SP rather than drifting. The exceptions (genuine drifters) are hard to predict reliably. For most horses, most of the time: take the early price.
When Early Price vs SP Matters Most
Horses known to be strongly fancied by their stable — identified through trainer interviews, jockey bookings and market whispers — will almost certainly shorten significantly before the off as stable money arrives. Taking the price before this money enters the market is the most direct and reliable way to secure value. For these horses, taking SP means accepting the price after the value has already been compressed out of it.
✅ Stable fancies — take early, alwaysIn a 20-runner competitive handicap where the money's destination is unclear, some horses will shorten and others will drift significantly. If your selection is not a well-known stable fancy and the morning market is thin — few early prices available, little price movement yet — SP betting can occasionally return a better price. This is the scenario where SP has the most relative merit versus early prices.
At minor meetings with limited media coverage, some bookmakers don't offer competitive early prices — or offer no early price at all. In these cases, SP may be the only practical option. Betfair SP (see below) is a consistently better alternative to bookmaker SP at these meetings — the exchange market is liquid enough to produce efficient prices even where the on-course betting ring is thin.
📊 Small meetings — Betfair SP beats bookmaker SPBest Odds Guaranteed (BOG)
Best Odds Guaranteed is the promotion that makes taking early prices strictly superior to SP betting at bookmakers who offer it — eliminating the only remaining reason to prefer SP over an early fixed price.
Under Best Odds Guaranteed, if you take an early fixed price and the SP returned is higher than your taken price, the bookmaker automatically upgrades your settlement to the SP. If the SP is shorter than your taken price, you keep your original fixed price. The taken price is always the floor — you can only benefit from BOG, never be harmed by it. It combines the certainty of a fixed price with the upside of SP.
BOG in Practice — Horse Drifts
You take 6/1 early. The horse drifts to 10/1 SP.
With BOG: settled at 10/1.
Without BOG: settled at 6/1.
BOG upgrades you to the better SP — identical outcome
to having waited for SP, with no downside risk.
BOG in Practice — Horse Shortens
You take 6/1 early. The horse shortens to 3/1 SP.
With BOG: settled at 6/1.
Without BOG: settled at 6/1.
BOG makes no difference here — but your early price
is already better than SP. You win either way.
Which Bookmakers Offer BOG
Most major UK bookmakers offer BOG on UK and Irish horse racing as a standard promotion — Bet365, William Hill, Coral, Ladbrokes, Betway and others. Terms vary: some apply BOG to all races; others restrict it by race type, time of day or bet type. Always confirm BOG applies to your specific bet before placing.
BOG Limitations to Know
BOG typically applies only to win bets and each way bets — not all bet types. It usually compares your price to the bookmaker SP rather than Betfair SP. Some bookmakers cap the BOG upgrade at a maximum price (e.g. no upgrade above 25/1). Free bet stakes may be excluded from BOG upgrades — check terms carefully for promotional bets.
At any bookmaker offering BOG, taking an early fixed price is objectively better than taking SP — you get whichever is higher, with no downside. There is no rational reason to take SP at a BOG bookmaker rather than the early price. Always take the early price at BOG bookmakers — and always compare early prices across bookmakers to take the best available price before the market moves.
Betfair SP — The Efficient Alternative
Betfair's Starting Price (BSP) is an entirely different mechanism from the traditional bookmaker SP — more efficient, lower margin, and more representative of the true market for most races. It is the preferred SP benchmark for professional bettors and analysts worldwide.
Betfair SP is determined by an automated process that matches unmatched bets at the moment the race starts. Bettors can request to back or lay horses "at BSP" — submitting their bet to be matched at whatever the BSP turns out to be. At the off, Betfair's algorithm clears these unmatched orders at the price that maximises matched volume — producing a market-clearing price that reflects the aggregate of all bettors' willingness to back and lay. No reporters, no on-course surveys — pure automated price discovery.
Why BSP Is More Efficient
BSP reflects global exchange money — not just the on-course betting ring at one racecourse. It incorporates the views of professional bettors, syndicates, trading algorithms and retail bettors worldwide. This depth of information makes BSP more efficient than traditional SP — less likely to be distorted by a single large on-course bet or a thin betting ring at a minor meeting.
BSP Carries a Lower Effective Margin
Unlike traditional SP — which carries a 15–25% overround — BSP is a market-clearing price with no embedded bookmaker margin. Betfair charges commission only on net winnings (typically 2–5%) rather than building a margin into the price itself. The effective margin on BSP bets is dramatically lower than bookmaker SP across most markets.
BSP as the Closing Line Benchmark
BSP is the most widely used closing line benchmark in professional horse racing analysis. Comparing the price you took to BSP — rather than to bookmaker SP — produces the most accurate measure of Closing Line Value (CLV). If you consistently beat BSP, the evidence for genuine edge is more compelling than beating bookmaker SP, which carries its own distortions.
BSP Can Be Volatile on Short-Priced Horses
On very short-priced horses (odds-on favourites), BSP can occasionally be higher than expected if strong lay pressure keeps the back price elevated. Conversely, on very long-priced outsiders with limited exchange liquidity, BSP can be lower than bookmaker prices. BSP is most reliable and most representative on horses priced between 2.00 and 20.00 in liquid markets.
Bookmaker SP vs Betfair SP — Side by Side
Bookmaker SP
Determined by: On-course reporter survey
Overround: 15–25% typically
Reflects: On-course betting ring only
Availability: All UK/Irish races, all bookmakers
Best for: Convenience, where online alternatives not available
Manipulation risk: Low but possible via large on-course bets
CLV benchmark quality: Moderate
Betfair SP (BSP)
Determined by: Automated market-clearing algorithm
Effective margin: 2–5% commission on winnings
Reflects: Global exchange market
Availability: Betfair only — most UK/Irish/international races
Best for: SP-style settlement at lowest margin
Manipulation risk: Extremely low at scale
CLV benchmark quality: Gold standard
If you are in a situation where SP settlement is the only or most practical option — betting on a small meeting without competitive early prices, using a telephone account, or placing a late bet without access to a fixed price — always use Betfair SP rather than bookmaker SP where possible. The lower effective margin and greater efficiency of BSP makes it unambiguously better for the bettor in SP-settled situations.
When SP Betting Makes Sense
For all the reasons above, SP betting is rarely the optimal choice for an informed bettor. But there are specific scenarios where it is legitimate or even advantageous.
No Competitive Fixed Price Is Available
At minor meetings or for races where few bookmakers offer a competitive fixed price, the choice may be between an uncompetitive fixed price and SP. In these cases, Betfair SP is almost always the best option — more efficient than a fixed price from a bookmaker offering a wide margin on a thinly traded race.
You Expect the Horse to Drift
If you have well-founded reason to believe your selection will drift in the market — perhaps well-informed knowledge that expected stable money is not coming, or that the horse is being deliberately over-priced — waiting for SP can produce a better return. This is a genuinely skilled use of SP betting but requires reliable intelligence rather than guesswork.
Ante-Post Bets Transferred to SP
Some ante-post bets — particularly on small races or those placed very early — are settled at SP because no fixed price is available that far in advance. In these cases SP is accepted as a condition of the bet rather than a choice. Being aware that a long-term ante-post bet will be settled at SP — rather than the price you expected — is important to clarify before placing.
You Are Systematically Using BSP for Value Betting
Some professional bettors and quantitative strategies operate systematically using Betfair SP — backing horses identified by model as underpriced at BSP, accepting BSP as settlement at the exchange's commission rate. This is a legitimate professional approach where the strategy's edge is expected to overcome the commission rate, and the scale of volume makes BSP the most practical settlement mechanism.
How SP Settlement Works in Practice
Understanding the mechanics of SP settlement — including Rule 4 deductions, each way SP settlement and joint favourites — prevents common surprises when bets are returned.
A win bet struck at SP is settled at the officially returned SP if the horse wins. If the horse loses, the stake is forfeit as with any losing bet. The SP used for settlement is the officially returned price — not the price displayed on any individual bookmaker's board at the time, but the officially returned SP published by the SP reporters.
📊 Settlement SP = officially returned price, not individual board priceEach way bets struck at SP settle both the win part and the place part at SP. The place terms are those applicable to the race — set based on the number of runners at the time of the race, not at the time the bet was placed. For each way SP bets, both the win and place parts of the settlement price are derived from the same officially returned SP.
If a horse is withdrawn after betting has opened but before the race starts, a Rule 4 deduction may apply to SP-settled bets on other runners. However, because SP is determined after the withdrawal — with the remaining field already adjusted — Rule 4 deductions on SP bets are handled differently from fixed-price bets. Most bookmakers apply Rule 4 to SP bets only in specific circumstances involving very late withdrawals. Check the specific bookmaker's terms.
📊 Rule 4 on SP bets is less common than on fixed-price betsWhen two or more horses are returned at the same SP (joint favourites or co-favourites), they are each settled at the full returned SP. There is no reduction applied to settlement because multiple horses share the same price — each SP-settled bet on any of the joint favourites receives the full SP if that horse wins or places.
✅ Joint favourites at SP: each settled at full shared priceCommon Questions
Yes — and this happens regularly, particularly with horses that drift in the market during the day. A horse that opens at 5/1 in the morning and drifts to 9/1 by the off will return an SP of 9/1 — longer than the early price. Bettors who took the early price at 5/1 would receive worse settlement than those who waited for SP or took a later price. However, this scenario is the exception rather than the rule — the majority of well-supported horses shorten from their morning price to SP rather than drifting. Best Odds Guaranteed eliminates this risk for bettors at BOG bookmakers: if the SP is longer, you receive the SP; if it's shorter, you keep your taken price.
There are a few legitimate reasons. Some bettors use systematic strategies where they identify horses underpriced at SP — taking BSP as settlement at the exchange is practical for high-volume automated betting. Some use SP because their betting approach involves making selections without monitoring the market actively — they select in the morning or the night before and accept SP as a convenience. For casual bettors on a range of races, SP eliminates the need to compare prices across bookmakers for each bet. However, for any bettor who takes their returns seriously, taking the best available early price at a BOG bookmaker almost always produces better long-term results than systematic SP betting at a bookmaker.
SP is primarily a horse racing concept — the result of horse racing's long history of on-course betting and the need for a regulated settlement mechanism before online betting existed. Greyhound racing also uses an SP mechanism for similar historical reasons. Other sports do not use SP in the same way — football, tennis and other sports betting is almost entirely fixed-price, where the odds you see when placing the bet are the odds you receive at settlement. The concept of a "starting price" in other sports is occasionally used informally to mean the odds at kick-off — but it is not a formal regulated mechanism as it is in horse racing.
A horse that is withdrawn after the betting ring has opened does not receive an SP — only runners that actually participate in the race receive an official SP return. A very late withdrawal (after the off in some cases, such as a horse that refuses to enter the stalls) may be treated differently depending on the circumstances. In these edge cases, bets on the withdrawn horse are typically voided and stakes returned, while Rule 4 deductions may be applied to other runners' returns based on the withdrawn horse's pre-race price.
Generally no — once a bet is placed at SP it is locked in at SP settlement. You cannot change the settlement method after the bet has been accepted. Going in the other direction — switching from a fixed price to SP — is similarly not possible once the bet is placed. If you want to change your settlement approach, the practical option is to cash out the existing bet (if the bookmaker offers cash-out) and place a new bet at the preferred terms. Some bookmakers allow editing of open bets before the race — check whether your bookmaker offers bet editing functionality if this situation arises.
The single most effective step you can take before any horse racing bet is to compare prices across bookmakers and take the best available early price. Our live odds comparison shows all bookmaker prices simultaneously — so you never have to settle for SP when a better fixed price is available.
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