How Bookmakers Detect and Limit Sharp Bettors (and How to Avoid It)

The Economist recently published an excellent article titled “The Battle to Stop Clever People Betting,” which explores the tools bookmakers use to identify and block data-savvy gamblers — and how some manage to get around them.

As the original piece is behind a paywall, what follows is a detailed summary highlighting its key ideas and insights:

• The article explains how sportsbooks actively profile customers from the very beginning. In many cases, this happens even before the first bet is placed.

• They look at very basic things: whether you bet from a phone or a computer, how you deposit money, whether you use e-wallets, how fast you bet after odds are released, what markets you choose, and even whether you are a woman.

• One line from the article is very revealing: “By the time a customer places his first bet, sportsbooks are 80–90% certain they know the lifetime value of the account.” In other words, they quickly decide whether you are likely to be a long-term loser or a long-term winner.

• Most recreational bettors behave in a predictable way. They bet close to kickoff, on popular leagues, on main markets, and they love parlays. They usually don’t care much about the odds.

• However, sharps behave in the opposite way. They bet early, when prices are more likely to be wrong. They target smaller leagues and derivative markets. They compare odds. They rarely use parlays. These behavioural differences are easy for bookmakers to spot.

• One of the most important tools sportsbooks use is Closing Line Value. If a bettor consistently gets better odds than the closing price in his first few bets, that is a huge warning sign. As the article puts it: “If it is consistently ahead of the market over his first ten wagers, he is highly likely to beat the book in the long run.” This is why closing odds matter so much, and why beating the close is one of the clearest signals of skill.

• Surveillance does not stop once you are identified as suspicious. Large betting groups use mathematical “risk scores” that are updated every six to eight hours to estimate the probability that a customer will end up unprofitable for the bookmaker. An internal document from GVC highlights e-wallet users, women and bets over €100 for extra scrutiny.

• Suspected sharps might be allowed only 30% of normal stakes. Confirmed sharps can be cut to 1%. At that point, betting seriously becomes impossible.

• Interestingly, bookmakers do not automatically restrict people who win a lot of money. If they believe someone is just lucky, they are happy to keep them playing, because luck often runs out.

• At the same time, sportsbooks actively look for “whales”: big, reckless losers with deep pockets. These players get VIP treatment, higher limits, free trips and special attention. But sometimes whales turn out to be sharps in disguise, and when that happens, limits disappear very quickly. One bookmaker in the article sums it up very clearly: “He’s betting into prices we’re comfortable with. If he wins, he wins.”

• Once a bettor is limited everywhere, the options are bad. Betting shops require disguises and are impractical at scale.

• Many professional bettors end up using other people to place bets for them, known as beards or mules. This is against the rules of every sportsbook and can be legally risky, but it is extremely common.

• To avoid detection, sharps are very careful. They never place the same bet from multiple accounts, they use different devices and locations, and some even drive around so that bets come from different addresses. Some go further and use a technique called “priming”: they intentionally make bad bets and lose money first, so the bookmaker raises their limits, and only then do they start betting seriously... Do you remember "The Color of Money" of Paul Newman and Tom Cruise?

• As one experienced sharp says in the article: “They want to prey on degenerates and irresponsible gamblers. So you want to dress yourself as the most degenerate, irresponsible gambler out there.”

• The most powerful strategy described is called “whale-flipping”. Sharps befriend big losers and get them to place bets on their behalf, hiding smart bets inside a large volume of bad ones.

• I personally remember taking a Bet365 account of a friend, who was in big losses, and win big for quite a long time until they block me. This was some years ago, I don't know if they are so patient now.

• Billy Walters, one of the most famous bettors in history, even wrote that Phil Mickelson placed bets for him at limits he could never get himself.

• Another great quote from the article captures the mindset perfectly: “You can come in like Dracula. But we prefer the mosquito way, taking a little bit of blood at a time.”

• When friends and family are no longer available, sharps turn to professionals known as movers, who manage networks of paid mules.

• Lower-level movers typically take 10–20% of winnings and no losses. Top-tier movers work with data-driven bettors, move large sums and usually split profits and losses 50/50.

• Even in this grey world, there is one authority nobody tries to deceive: “God may forgive, but the IRS shows no mercy.”

• Some countries have tried to regulate betting limits. Spain is mentioned as a place where some bettors have successfully sued bookmakers to reopen accounts. Australia has minimum bet rules in horse racing. But regulators themselves admit the reality. As Britain’s Gambling Commission put it: “Being a successful bettor is not a protected characteristic.”

• The final and most interesting point is that many sharps do not actually want limits to disappear.

• If bookmakers were forced to accept everyone, odds would get worse, limits would fall for all customers, and many exploitable markets would simply vanish. One professional sharp sums it up perfectly: “Limits are the best thing that’s happened to me. It keeps the people that can’t scale where they are, and makes me money.”

• This article confirms something serious bettors already know. Finding value is hard, but surviving long enough to bet it is often the real challenge.