What is brushing arbitrage?

Brushing, also known as "water brushing," is a form of arbitrage behavior on gambling platforms. It takes advantage of different preferential offers between gambling platforms by placing bets on two or more platforms, such as betting on over and under outcomes. For example, placing a large bet on platform A and a small bet on platform B. This results in an outcome that is close to a zero-sum game, allowing the user to profit from the price difference. A common approach is to bet on opposite outcomes on two platforms, which again results in a close-to-zero-sum game. If we deduct the platform fees, the outcome may be negative, but thanks to the rebate offers provided by the platforms, actual profits can be generated. Now, let's start by discussing the promotional schemes offered by different gambling platforms. To attract gamblers, platforms typically provide various incentives. Among these, the most common are rebate schemes based on turnover. In most cases, these rebates are primarily given to higher-level agents. As far as I know, a high-level agent can receive approximately $280 in rebates for every $10,000 wagered. In order to retain customers, agents often distribute a portion of these rebates to the players. This has led to the practice of brushing arbitrage, where bets are placed on different platforms to obtain rebates and price differences.