An arb only pays if you have an account on both sides, so the right question isn't which book is best. It's which set of books, held together, catches the most arbs. This picks that set from every credible arb we've tracked over the last 30 days, then works out what a fixed bankroll in each book earns.
State-licensed US sportsbooks only.
$2,000 split 4 ways is $500 a leg, so about $1,004 staked per arb.
Dashed line: what your bankroll can place, 12 arbs/night. Supply is above that line, so bankroll is the limit, not opportunities. More money per book earns more.
| Caesars | betPARX | BetMGM | FanDuel | DraftKings | Hard Rock Bet | |
|---|---|---|---|---|---|---|
| Caesars | 5.1 | 4.2 | 4.3 | 3.2 | 1.5 | |
| betPARX | 5.1 | 3.6 | 2.9 | 2.4 | 1.8 | |
| BetMGM | 4.2 | 3.6 | 3.2 | 2.3 | 2.8 | |
| FanDuel | 4.3 | 2.9 | 3.2 | 3.5 | 2.6 | |
| DraftKings | 3.2 | 2.4 | 2.3 | 3.5 | 1.7 | |
| Hard Rock Bet | 1.5 | 1.8 | 2.8 | 2.6 | 1.7 |
1. Which books. An arb with books L is only placeable if you hold an account at every book in L. For a set of accounts S:
A(S) = ΣL ⊆ S count(L) / 30 nights
We score every 6-book combination of the most active books by the total edge it captures, Σ count(L) · roi(L), and keep the best. That set gives 46 arbs/night here. Weighting by ROI matters: some pairs produce plenty of arbs at around 0.5%, which pay less than fewer arbs at 2% once your bankroll is the limit. We check every combination rather than adding one book at a time, because a single book captures nothing on its own.
2. How much each arb makes. With B = $2,000 per book, c = 4 arbs per book per night, and ℓ = 2.01 legs per arb:
stake per leg s = B / c = $500 stake per arb T = ℓ · s = $1,004 profit per arb T · r = $19.01 (r = 1.89%)
3. How many you can place. Every leg uses one of a book's c nightly slots:
capacity N_cap = k · c / ℓ = 6 · 4 / 2.01 = 12 placed N = min(A, N_cap) = 12 per night P = N · T · r = $227 30 nights 30 · P = $6,815
Supply is above capacity, so this reduces to P = k · B · r: your whole $12,000 turns over once a night at 1.89%.
“Locked-in” means both legs filled at the quoted prices. In practice, prices move before the second leg is placed, books cap stakes, some bets get voided, and books limit accounts that arb often. Treat these numbers as a ceiling you work toward, not a promise. When supply is above capacity you can choose the best-paying arbs each night, so the median ROI used here is on the conservative side. Stakes also free up only once bets settle. A night game settles by morning, but a futures leg locks that money up much longer.