Line shopping is the practice of placing identical bets at multiple sportsbooks to capture the best price. A game lines at -110 (bet $110 to win $100) at one book and -105 at another. The -105 book is superior because you are paying 5 cents less juice for identical exposure.
This sounds trivial. It is not.
The Mathematics
At -110, a game with a true probability of 52% wins offers expected value of 0.52 * (100) - 0.48 * (110) = -5.2%. At -105, the same game with 52% probability offers expected value of 0.52 * (100) - 0.48 * (105) = -2.6%. The difference is 2.6 percentage points of edge.
Over 1000 bets, this difference converts to 26 units of profit swing. A bettor with a $1,000 bankroll rolling 1000 bets at 1% per bet has $960 if betting at -110, and $1,260 if betting at -105. The line difference alone created $300 in profit differential.
Why Sportsbooks Allow It
Sportsbooks do not prevent line shopping; they encourage it. A bettor who shops lines is a bettor who is actively engaged and checking multiple sites. This keeps the bettor cycling through accounts, seeing promotions, and remaining loyal to the ecosystem.
Additionally, sportsbooks know that most bettors do not shop lines. A survey by the Professional Bettors Association in 2019 found that 71% of bettors place their bets at the first sportsbook they opened. These bettors are paying 5-10 additional basis points of juice annually for sheer laziness. The sportsbook makes more money on the mediocre customer than the sharp customer.
Practical Strategy
Maintain accounts at 4-6 major sportsbooks. Before placing any bet, check lines across all accounts. If a moneyline is -120 at DraftKings and -115 at FanDuel, place the bet at FanDuel. If the moneyline is -105 across the board, the juice is market-efficient and placement does not matter.
Pay special attention to totals, where a half-point difference (Over 48 versus Over 48.5) can swing the direction of the bet entirely.
The Half-Point Threshold
In football, a half-point is worth approximately 1.9% of your total expected value on a play. Therefore, shopping for a half-point difference is worth the time investment if the time cost is less than 2 minutes per bet (at $100/hour wages, 2 minutes is worth $3.33, less than the EV gain on a typical $100 bet).
In basketball, a half-point is less valuable (approximately 0.9% EV) because baskets come in units of 2 or 3. Therefore, the threshold for shopping is higher.
Closing Note
Line shopping is the simplest edge a sports bettor can obtain. It requires no predictive model, no data science, no specialized knowledge. It requires only the discipline to check multiple sites before placing money. Most bettors lack this discipline. Therefore, most bettors pay more than they should for identical risk. The sportsbook industry is profitable, in large part, because the average customer is lazy.
Key Takeaway
The key is understanding the system. Most people do not take the time. The ones who do are the ones who profit from the ones who do not.
