What Is the Industry Starting Price (ISP)?

The Industry Starting Price (ISP), often simply called the Starting Price (SP), is the official odds at which a horse or runner is valued at the precise moment a race begins. These odds are calculated from a consensus of prices offered by a selected sample of major off-course bookmakers and are used to settle bets placed without pre-agreed fixed odds.

In practical terms, if you place a bet at "Starting Price" with a bookmaker and don't lock in specific odds beforehand, your bet will be settled at the ISP when the race starts. For example, if a horse you backed has an ISP of 5/1 (decimal 6.0), a £10 winning bet returns £60 (your £10 stake plus £50 profit).

The ISP represents the final market consensus—the odds that reflect the aggregate betting sentiment of major bookmakers just before the off. This system ensures fairness for off-course bettors who cannot be at the racecourse to observe live odds movements, and it provides a standardized settlement price across all bookmakers offering ISP bets.

ISP in the Broader Betting Context

The ISP sits within the framework of fixed-odds betting, which is the traditional betting system used in the United Kingdom and many other jurisdictions. Unlike pari-mutuel systems (common in Australia and the United States), where payouts are calculated from the total betting pool, fixed-odds betting like ISP relies on bookmaker-set prices.

The key difference is that ISP is a consensus price derived from multiple bookmakers, while other odds types reflect either individual bookmaker decisions or pure market-driven pricing.

How Is the Industry Starting Price Calculated?

The Calculation Mechanism

The ISP is not calculated as a simple average of bookmaker odds—this would be too vulnerable to manipulation. Instead, it uses a median consensus approach designed to prevent collusion and ensure fairness.

Here's how the process works:

1. Sample Selection: The Starting Price Regulatory Commission (SPRC) selects a sample of major bookmakers (typically 20-24) that collectively represent a significant share of the UK betting market.

2. Odds Collection: At the moment the race starts ("the off"), the odds offered by each bookmaker in the sample are recorded.

3. Ordering: These odds are arranged from the highest odds offered to the lowest.

4. Median Calculation: The ISP is determined as the lowest odds in the upper half of the sample. If there are 24 bookmakers, the 12th bookmaker's odds (from the top) becomes the ISP.

Example: If 10 bookmakers are offering the following odds on a horse (in decimal format):

The ISP would be 6.5 (11/2) — the lowest odds offered by a bookmaker in the top half (positions 1-5).

This methodology ensures that:

• No single bookmaker can artificially inflate or deflate the ISP
• The price reflects genuine market consensus
• Bettors receive a fair price based on widespread market sentiment

The Role of the Starting Price Regulatory Commission (SPRC)

The Starting Price Regulatory Commission (SPRC), operating under the authority of the British Horseracing Authority, is the independent body responsible for overseeing the integrity of the ISP system. Their responsibilities include:

• Selecting the sample of bookmakers used for ISP calculation
• Setting and enforcing rules for ISP determination
• Monitoring for manipulation or collusion
• Publishing ISP data for transparency
• Handling disputes related to SP settlements

The SPRC ensures that the ISP system remains fair, transparent, and resistant to manipulation. This regulatory oversight is critical to maintaining confidence in the betting market, particularly for off-course bettors who cannot directly observe racecourse conditions.

Why Not a Simple Average?

You might wonder why the ISP doesn't simply use the average of all bookmaker odds. The answer lies in market integrity.

If the ISP were a simple average, bookmakers could potentially collude by offering artificially skewed odds—some offering inflated odds while others offer depressed odds, with the average still falling within an acceptable range. By using the median of the upper half, the ISP is weighted toward the most competitive prices, making collusion far more difficult.

Additionally, this methodology ensures that the ISP reflects the odds that a substantial bettor (typically around £500) could actually obtain from a bookmaker at the point of the off, rather than a theoretical average that no single bookmaker actually offered.

When and Why Was the ISP System Introduced?

Historical Origins: The 19th Century Birth of Starting Prices

The concept of a standardized "starting price" emerged in the early 19th century, during the professionalization of British horse racing. The earliest recorded references to starting prices date to 1805, when betting on horse races was becoming increasingly formalized.

However, the modern SP system was truly established around 1874, following decades of evolution in bookmaking practices. The catalyst for formalization was the growth of off-course betting—wagers placed away from the racecourse. Without a standardized SP, there was no fair way to settle bets for customers who weren't at the track to observe live odds.

Tattersalls, originally founded in 1766 as Europe's premier bloodstock auction house, evolved to establish the influential Tattersalls betting ring at racecourses. This ring became the epicenter of SP determination, where leading bookmakers would declare their odds, and a consensus price would be established. This system allowed credit bettors and off-course punters to receive fair settlement prices based on genuine market conditions.

By the late 19th and early 20th centuries, the SP system had become integral to British horse racing, enabling:

• Nationwide betting networks where customers could place bets at any bookmaker
• Standardized settlement across all bookmakers
• Large-scale betting operations without excessive bookmaker liability concerns
• Public confidence in fair betting practices

The Major 2020 Shift: From On-Course to Off-Course Calculation

For over 140 years, the Starting Price was determined by on-course bookmakers—those operating betting booths at the racecourse itself. These on-course bookmakers would observe the betting patterns and odds movements on the track and establish the SP based on their collective market assessment.

This system worked well for over a century, but COVID-19 changed everything.

In March 2020, the United Kingdom entered lockdown. Horse racing was briefly suspended, and when it resumed in June 2020, strict restrictions were imposed:

• No crowds were allowed at racecourses
• Bookmakers were prohibited from operating on-course
• Racing continued, but without the traditional on-course betting market

The Starting Price Regulatory Commission was forced to conduct an urgent review. The findings were striking: only 1.4% of horse racing bets were placed on-course under normal circumstances. The vast majority of bets—over 98%—were placed off-course through online bookmakers.

Given this reality, the SPRC made a permanent decision: effective June 1, 2020, the ISP would henceforth be calculated from off-course bookmakers rather than on-course bookmakers.

This shift meant that instead of basing the SP on a sample of on-course prices (which represented only a tiny fraction of actual betting), the ISP would be based on the prices offered by major off-course operators—the actual market where the vast majority of bettors were placing their money.

Modern ISP: The Post-2020 Structure

Today, the ISP is calculated from a sample of 20-24 major off-course bookmakers selected by the SPRC. These bookmakers collectively represent a substantial share of the UK betting market and include operators such as major online sportsbooks.

The shift to off-course calculation has had several consequences:

For Bettors:

• The ISP now reflects the actual market where most people bet
• Off-course bettors get a price based on genuine market conditions
• There is greater transparency, as off-course odds are digitally recorded and easily verifiable

For Bookmakers:

• The ISP is more influenced by online market dynamics
• Bookmakers must be more competitive on odds to avoid being selected for the ISP calculation
• The system is less influenced by individual bookmaker decisions at the track

For the Sport:

• The ISP maintains its integrity as a fair settlement price
• Racing data and betting information remain valuable for analysis
• The system continues to support the betting ecosystem that funds racing

ISP vs. BSP: What's the Difference?

One of the most common sources of confusion for bettors is the difference between ISP (Industry Starting Price) and BSP (Betfair Starting Price). While they sound similar and serve a similar purpose, they are calculated in fundamentally different ways.

Betfair Starting Price (BSP) Explained

Betfair is a betting exchange—a platform where bettors bet against each other rather than against a bookmaker. Instead of a bookmaker setting odds, prices on Betfair are determined by supply and demand in the market, similar to a stock exchange.

The Betfair Starting Price (BSP) is the final odds at which all unmatched bets on Betfair are settled when a race starts. It represents the consensus price from thousands of individual bettors and layers (those offering odds) on the exchange.

Key characteristics of BSP:

• Market-driven: Determined purely by bettors' willingness to back or lay
• No bookmaker margin: BSP reflects pure market sentiment (before Betfair's commission)
• Highly efficient: The market is generally considered more accurate at pricing than bookmakers
• Lower overround: Typically around 100% (before commission), compared to ISP's 110-130%

Key Differences in Calculation

The critical difference is that ISP reflects bookmaker opinion, while BSP reflects bettors' opinion. These are not always the same.

Which Is Better for Bettors?

The answer depends on the odds range you're betting at.

Research by the Horseracing Bettors Forum (HBF) comparing ISP and BSP found:

• At longer odds (15/1 and above): ISP is typically better for bettors. The ISP tends to be shorter (better value) than BSP at these prices.
• At medium odds (4/1 to 14/1): ISP is typically worse for bettors. The ISP is markedly longer (poorer value) than BSP, particularly in the 4/1 to 15/2 range where many each-way bets are placed.
• At short odds (shorter than 5/4): ISP is slightly worse for bettors. Favorites and second favorites tend to be shorter at ISP than at BSP.

Practical Implications:

If you're backing a 20/1 shot, you're likely to get better value settling at ISP than BSP. But if you're backing a 5/1 favorite, you're probably better off betting at a fixed price on a bookmaker's website than settling at ISP.

Common Misconceptions About ISP

Myth #1: ISP Is Always Fair

Many bettors assume that because ISP is calculated by a regulatory commission, it must be "fair" in the sense of being neutral or unbiased toward bookmakers. This is incorrect.

The ISP, like all fixed-odds betting prices, includes an overround—a built-in margin that favors the bookmakers. The overround is the amount by which the total implied probability of all outcomes exceeds 100%.

For example, if a race has three horses with ISP odds of 2/1, 2/1, and 2/1 (each with an implied probability of 33.3%), the total implied probability is 99.9%—very close to fair. But if the ISP odds are 2/1, 2/1, and 1/1 (implied probabilities of 33.3%, 33.3%, and 50%), the total is 116.6%—an overround of 16.6%.

This overround is how bookmakers ensure profitability. The ISP is "fair" in the sense that it reflects genuine market consensus, but it is not fair in the sense of being unbiased toward bookmakers.

Myth #2: ISP and SP Are Completely Different Things

Some bettors believe that "ISP" and "SP" are entirely different concepts. In reality, ISP is the modern name for what was traditionally called SP.

Before June 2020, the SP (Starting Price) was calculated from on-course bookmakers. After June 2020, the same system was renamed the ISP (Industry Starting Price) to reflect the fact that it was now being calculated from off-course industry bookmakers.

The terms are now used interchangeably:

• SP = Starting Price (the traditional name)
• ISP = Industry Starting Price (the modern name, post-2020)

When someone refers to "settling at SP," they mean the same thing as "settling at ISP."

Myth #3: ISP Is Always Better Than Betting at Fixed Odds

Some bettors believe that taking the ISP is always a better strategy than locking in fixed odds before the race. This is not universally true.

The decision to take ISP versus fixed odds depends on several factors:

When ISP might be better:

• You believe the odds will shorten between now and the off (your horse will be backed more)
• You're backing a long shot that might drift
• You don't have a strong opinion on the odds

When fixed odds might be better:

• You believe the odds will lengthen between now and the off (your horse will be backed less)
• You've identified value at current odds and want to lock it in
• The horse is a favorite likely to shorten as race time approaches
• You have strong analytical reasons for your assessment

The ISP is a settlement mechanism, not inherently a better or worse betting strategy—it depends on your assessment of how odds will move.

How ISP Affects Your Betting Strategy

When to Bet at ISP

Taking the ISP (rather than locking in fixed odds) makes sense in specific scenarios:

1. Long-Shot Bets: If you're backing a horse at 15/1 or longer, ISP often provides better value than BSP or other alternatives.

2. Uncertain About Odds Movement: If you're unsure whether a horse will shorten or drift, ISP allows you to wait until the off to see the final market consensus.

3. Exchange Fallback: If you're primarily an exchange bettor and your bet doesn't match on Betfair, you can fall back to ISP as a settlement mechanism.

4. Off-Course Betting: If you're betting with a traditional bookmaker rather than an exchange, ISP is the standard settlement mechanism for "SP bets."

5. Late Betting: If you're placing a bet very close to the off, there's little time for odds to move significantly, so ISP and current fixed odds will be similar.

Not Taking the ISP (locking in fixed odds) makes sense when:

1. You've Identified Value: If you believe current odds are generous compared to the horse's actual chances, lock them in.

2. Favorite Backing: If you're backing a favorite that's likely to shorten, take the fixed odds now rather than risk a shorter ISP.

3. Drift Prediction: If you believe a horse will drift as race time approaches, take current odds rather than risk a longer ISP.

ISP Overrounds: What You Need to Know

The overround is the bookmakers' built-in margin. Understanding how overround varies across different odds ranges is crucial for assessing betting value.

Research on ISP overrounds shows:

• At very short odds (favorites): Overround tends to be 100-110%, relatively tight
• At medium odds (4/1 to 10/1): Overround tends to be 120-140%, quite substantial
• At long odds (15/1 and beyond): Overround tends to be 110-130%, moderate

This means that medium-priced horses (around 4/1 to 10/1) have the highest overround, making them less favorable for bettors from a value perspective. In contrast, very long shots (20/1+) sometimes have lower overrounds, making them potentially better value.

For example:

• A horse at 2/1 (favorite) might have a 108% overround—you're only giving away 8% to the bookmaker
• A horse at 5/1 (medium price) might have a 125% overround—you're giving away 25% to the bookmaker
• A horse at 25/1 (long shot) might have a 115% overround—you're giving away 15% to the bookmaker

Understanding these overround patterns helps you identify which odds ranges offer the best value.

Comparing ISP to Pre-Race Fixed Odds

A common strategic question is: Should I lock in fixed odds now, or wait for the ISP?

This decision hinges on predicting odds movement:

Lock in fixed odds if:

• Current odds are generous (you believe the horse is underpriced)
• The horse is a favorite likely to shorten
• You have strong analytical reasons for your assessment
• You want to eliminate uncertainty

Wait for ISP if:

• Current odds seem fair but might drift
• The horse is a long shot that might shorten (giving you better ISP value)
• You're uncertain about market movement
• You're betting late (close to the off)

Historical data shows that:

• Favorites tend to shorten from morning odds to ISP (on average)
• Long shots tend to drift from morning odds to ISP (on average)
• Medium-priced horses show mixed patterns

Therefore, a simple strategic rule might be:

• Favorites: Lock in fixed odds early
• Long shots: Consider waiting for ISP
• Medium prices: Analyze the specific race

Frequently Asked Questions About ISP

Q: What does ISP stand for?

A: ISP stands for Industry Starting Price. It's the official odds calculated from a consensus of major off-course bookmakers at the moment a race begins. The term "Industry" reflects that it's calculated from the betting industry (bookmakers) rather than from on-course prices. Before June 2020, this was simply called the "Starting Price" (SP), and the terms are still used interchangeably today.

Q: How is the ISP different from the odds I see on a bookmaker's website?

A: The odds you see on a bookmaker's website are that specific bookmaker's prices, which can vary significantly. The ISP is a consensus price calculated from 20-24 major bookmakers. The ISP is used to settle bets placed "at starting price" with a bookmaker, while the odds on the website are the bookmaker's current fixed odds. The ISP is typically determined at the moment the race starts, while website odds are constantly changing.

Q: Why did the ISP change in 2020?

A: In June 2020, the Starting Price Regulatory Commission made a permanent shift from calculating the SP based on on-course bookmakers to calculating it from off-course bookmakers. This was prompted by COVID-19 lockdowns that prevented on-course betting, but the change became permanent because data showed that only 1.4% of horse racing bets were placed on-course anyway. The off-course calculation better reflects the actual betting market where 98.6% of bets occur.

Q: Is ISP better than BSP (Betfair Starting Price)?

A: It depends on the odds. At longer odds (15/1+), ISP tends to be better for bettors. At medium odds (4/1 to 14/1), BSP tends to be better. This is because ISP includes a larger bookmaker overround at medium prices, while BSP, being exchange-based, has a lower overround overall. The best strategy is to compare ISP and BSP odds for the specific race you're interested in.

Q: Can I bet at ISP online?

A: Yes, you can place "Starting Price" or "SP" bets with most online bookmakers. When you place an SP bet, you're agreeing to settle at the ISP when the race starts, rather than at the fixed odds displayed at the time you placed the bet. This is a standard betting option offered by most major bookmakers.

Q: What happens if there's a Rule 4 deduction?

A: If a horse is withdrawn from a race, a Rule 4 deduction applies to reduce payouts proportionally. This deduction is applied to ISP bets just as it is to any other bet. The ISP itself is not affected by Rule 4 deductions—only the payout is reduced for bettors who backed the withdrawn horse.

Q: How long before the race start is the ISP determined?

A: The ISP is determined at the exact moment the race starts (the "off"). This is why it's called the "starting price." The odds from the selected sample of bookmakers are recorded at the moment the race begins, and the ISP is calculated immediately thereafter, typically within seconds.

Q: Is the ISP published publicly?

A: Yes, the ISP is published publicly by the Starting Price Regulatory Commission and is widely available through racing data providers, bookmakers' websites, and betting analysis platforms. This transparency is essential for maintaining market integrity and allowing bettors to verify settlement prices.

Q: Can bookmakers manipulate the ISP?

A: The ISP system is specifically designed to prevent manipulation. By using a median consensus from 20-24 bookmakers (rather than an average), and by selecting the lowest odds in the upper half, the system makes it extremely difficult for bookmakers to collude. Additionally, the Starting Price Regulatory Commission actively monitors for suspicious patterns. Manipulation is theoretically possible but practically very difficult.

Q: Should I always take the ISP, or should I lock in fixed odds?

A: This depends on your assessment of odds movement. Lock in fixed odds if you believe current prices are generous or if you're backing a favorite likely to shorten. Consider taking the ISP if you're backing a long shot that might drift, or if you're uncertain about how odds will move. There's no universally "correct" answer—it depends on your analysis and risk tolerance.

Related Terms

• Starting Price
• SP
• Betfair Starting Price (BSP)
• BOG (Best Odds Guaranteed)
• Overround
• Fixed-Odds Betting
• Each-Way Betting
• Rule 4 Deduction