How Bookmakers Work

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What does a bookmaker do?

A bookmaker organizes and conducts various types of gambling activities. It’s not limited to sports — bets can be placed on politics, culture, television, and more. Serious bookmakers, like BetBoom, have analytical departments that create odds for events. Employees are well-versed in the sports fields relevant to their work.

History

The origins of sports betting go back to Ancient Rome. Initially, bets were placed at hippodromes. Later, people started betting on cockfights.

Sports-related betting in its modern form began in the 19th century. Bets were placed directly on the event at hand. This marked the beginning of the bookmaker profession, which at first was known as a “professional wagerer.” The birthplace of modern bookmaking is England, which still leads the world in sports betting.

In our country, the first betting shop opened in Moscow at the end of the last century. Its popularity rapidly grew across the post-Soviet space. The rise in popularity can be explained by people’s natural inclination toward gambling.

Every new bettor carries the expectation of potential success. People believe that betting will provide them with income. However, in the long term, most bettors end up losing. Relying solely on luck, they forget that this is neither roulette nor the forex market. Betting requires serious effort — you shouldn’t depend on luck. To increase the chance of success, analysis and strategy are necessary.

Patience, willpower, and common sense help generate profit. Overconfidence is a poor advisor.

How are odds calculated?

Bookmakers analyze the chances of competitors. Both analytical and heuristic methods are used. Analytical methods involve statistics and mathematics. Heuristic methods use expert opinions. Combined, these approaches produce a range of probable outcomes.

Mathematical probability is expressed as numbers (0–1) or percentages. Then the probability is converted into odds. These are the “pure odds,” but they are not shown to the customers. Otherwise, the bookmaker wouldn't profit. Next, the bookmaker increases the total probability to more than 100%, typically to around 115%. The excess percentage represents the margin (the bookmaker’s profit). This margin is embedded in the odds.

In most matches, the favorite wins. In such cases, the bookmaker would lose money, which is unacceptable for business. Therefore, odds for the favorite are intentionally lowered. This protects the bookmaker by overestimating the favorite’s chances. However, favorites can also lose. Regardless of the outcome, the bookmaker remains profitable.

It is safer for a bookmaker to overestimate the favorite than to underestimate them. The business is driven not by true probabilities but by the displayed odds. Thus, the opponent’s real chances don’t matter — any outcome ensures bookmaker profit.

In practice, it’s impossible to precisely calculate the probabilities or predict how the money will be distributed among bets. There will always be inaccuracies. The odds for the favorite are initially lowered to guarantee profit. A margin of 15–20% is typically added to bets on the favorite. The highest profit is achieved by balancing the amounts wagered.

Bookmaker operations

A bookmaker must be competitive. This includes legal compliance and guaranteed payout of winnings.

Analysts

A bookmaker is not a totalizator. They set their own betting lines and calculate odds using data from the analytical department. If necessary, limits are applied. The bookmaker may create the line themselves or purchase one from foreign providers — but buying lines does not guarantee success. They still need to adapt the line analytically.

This includes considering the popularity of certain sports in specific regions, selecting key events from the line, checking for errors, and calculating acceptable margins.

The analysts’ work does not end here.

Once odds become publicly available, analysts begin monitoring player activity. The initial odds remain valid only until the first bets are placed. After that, the odds are adjusted depending on the amount of money wagered. To increase attractiveness, odds may be raised. If a large imbalance occurs, limits are applied, and events may even be removed from the line.

In live betting, odds change instantly. Players act quickly — delays lead to losses.

Marketers

The internet is saturated with bookmakers. Professionals choose based on wide betting markets and high odds — but they make up only about 10% of all players. The remaining bettors choose spontaneously or out of habit.

When there is a large flow of players, the bookmaker’s workload increases. Effective marketing is required: attracting traffic, designing bonuses and free bet mechanics, and ensuring a comfortable betting experience. If a player dislikes something, they will switch to another bookmaker.

Developers, designers, product managers

Their job is to ensure the site loads within seconds, works continuously, and provides transparency and intuitive navigation. Players should be able to deposit and withdraw winnings in just a few clicks.

They also adapt the website for mobile screens and may develop mobile apps.

Security

Some players attempt to cheat bookmakers in hopes of easy money. The security team verifies all suspicious transactions. Accounts can be blocked pending investigation.

Support service resolves disputes and builds customer loyalty.

Accountability to regulatory authorities is handled by legal and financial departments. The bookmaker operates legally within existing laws.

Types of bookmaker clients

Occasional player

These are people who occasionally watch sports — at home on the couch or in a bar with friends. They are not sports fans. Betting enhances the excitement and adds the potential of winning.

Fan

Fans are easy to identify — they follow one team, watch every match, know the roster and news. Bets enhance the emotional experience. Sometimes fans bet against their own team — the emotional win softens the financial loss.

Sports enthusiast

These players are sports experts. They prefer one sport, make rational decisions without emotion, know the strengths and weaknesses of teams, and may even publish expert predictions. They also place bets based on their analysis.

Gambler

The thrill comes not from the sporting event but from betting itself. Bets are placed based on emotions. Chasing large odds and accumulator bets gives them excitement. Winning generates a desire to place another bet — to relive the emotion.

Professional

They have deep knowledge of the sport and betting mechanics. Thanks to smart decisions and risk management, bookmakers often lose money on them. They don’t cheat — they simply know what they’re doing.

Tricksters and cheaters

Some dishonest players try to make money off the bookmaker. They exploit welcome free bets and register multiple accounts. Bookmakers track such schemes and block accounts without refunds.

Arbitrage (surebet) strategies are common — placing complementary bets at different bookmakers to ensure a guaranteed profit. Bookmakers strongly oppose this because it undermines the meaning of betting. They develop algorithms to detect arbitrageurs and permanently block accounts.

Another trick is to place bets ahead of time based on early info from live events (e.g., being at the match and placing a bet before the bookmaker updates the odds).
Sometimes bookmakers also use tricks (to reduce expenses).

Consistent winning by a player is a red flag. Bookmakers fight back by lowering limits, narrowing the betting line, delaying payouts, or even blocking accounts. However, legal bookmakers do not use such practices — this is an indicator of a trustworthy operator.