Arbitrage betting risks, and how people manage them

Arbitrage removes the risk of the game's result, not every risk. The ways an arb actually loses money are operational: one leg gets voided as an obvious error, the two bets settle under different rules, a maximum stake stops you placing the full leg, the price moves before you place the second bet, or the book limits your account. Each of these leaves you holding one ordinary bet instead of a hedged pair, and each has a routine that keeps the damage small. The examples below use the $1,000 NBA total from how to find arbitrage bets: $487.73 on Over 224.5 at +108 and $512.27 on Under 224.5 at −102.

Voided bets and obvious-error rules

Sportsbooks' house rules let them cancel, or resettle at a corrected price, bets taken at a price that was a mistake. DraftKings' rules, for example, count as an error a bet accepted at odds "meaningfully different" from the odds similarly situated US sportsbooks offered for the same bet at the time. The version filed with the Massachusetts Gaming Commission also makes voiding a bet there subject to the commission's approval, with the commission notified before any action is taken — so how much protection you have depends on your state's regulator as well as the book. The arb risk is obvious: the prices most likely to form a large arb are the prices most likely to be errors.

Mismatched settlement rules

Two bets that look like opposite sides can both lose if the books settle them differently. Overtime is the common case: DraftKings' general rules count overtime and shootouts in a two-way moneyline but not in a three-way moneyline, so a two-way moneyline paired with a three-way market grades differently when regulation ends level. Sport rules can override that: its football rules count overtime in all bets, three-way moneyline included, but not in its half-time/regulation-time double result. MLB bets can depend on listed pitchers; tennis bets on what happens if a player retires; player props on whether the player takes the field. The guides on listed pitchers and overtime and retirement rules cover the specific traps.

Maximum bet caps

Books cap the stake they will take on a market, and caps are often lowest on exactly the smaller markets where arbs appear. If one leg is capped, the other leg has to shrink to match, and so does the profit. Finding out after the second leg is placed leaves you over-exposed on one side.

The price moving between legs

Every second between the first and second bet is a second in which the second price can move. If it does, you face the same choice as after a void: place the second leg at the new price for a smaller profit or small loss, or hold an unhedged bet you did not intend to make. The void example above is the arithmetic for both. The sensible default is to close the position at whatever it costs, because the alternative is a full-size bet on one side of a coin flip.

Account limits and restrictions

The longer-term risk is the account itself. Books that see a customer consistently taking prices that are out of line with the market often reduce that customer's maximum stakes, sometimes to a few dollars. That does not lose money on past bets, but it ends the account's usefulness for arbitrage and for promotions. The limits guide and why sportsbooks limit bettors explain what books look for, and bet sizing to avoid limits covers the habits people use to keep accounts open longer.

Smaller costs that eat thin margins

On a 1.45% arb, small frictions matter. Exchanges and prediction markets charge fees that come off the return — see Kalshi fees. Money sits in several accounts at once, and withdrawals can take days. And the two legs are separate wagers at separate books, so they may not simply net against each other for tax purposes; the taxes guide has general information, and a tax professional can tell you how it applies to you.

How TrueEdge helps with these

The Arbitrage board marks legs it judges to be a likely mispricing — the ones most at risk of a void — shows when each pair was detected so stale prices are visible, lets you filter out quotes older than a set age, and has an All books view that shows your second-best cover before you place anything. It cannot read a book's settlement rules or your stake cap for you; those checks are still yours. The arbitrage walkthrough includes what to do when a second leg moves.