Sportsbooks limit a player by cutting how much that account is allowed to bet, and the accounts that beat the closing line are the ones most likely to be cut. A memo to the Massachusetts Gaming Commission, built from operators’ own data and reported by Covers in September 2025, found that “players who consistently beat the closing line are more likely to have a lower stake factor (i.e., have their limit lowered).”
The same analysis put the scale in proportion: 0.64% of Massachusetts sports betting accounts carried a limit as of the previous December. Of those, 57.6% were limited to between 1% and 24% of the default bet amount.
What the house rules allow
The right to limit is written into the rules every customer accepts. FanDuel’s Massachusetts house rules, approved by the state’s Gaming Commission on March 27, 2025, set the maximum bet at $5,000,000 and then reserve “the right to set a lower or higher maximum bet wager amount per customer for any offered event and/or wager type.”
The same rules let FanDuel decline bets “or to scale back the stakes (on a per user or aggregate basis),” and cap winnings at $1 million per bet, applied to “any one customer, or group of customers acting together.” Caesars’ Massachusetts house rules are shorter on the point: “Management in its sole discretion reserves the right to refuse any wager(s),” and its $1,000,000 maximum “can be restricted or increased” per customer.
Outside the United States, the wording goes further. William Hill’s UK terms, version 2024/1.3, say it may “restrict, suspend or close your Account at any time on no less than 14 days’ written notice.” That clause names no condition beyond the notice.
| Sportsbook rules | Maximum bet | Can set a limit per customer |
|---|---|---|
| FanDuel (Massachusetts) | $5,000,000 | Yes, per event or wager type |
| Caesars (Massachusetts) | $1,000,000 | Yes, per customer, sport or event |
Why winning bettors get limited
The book’s edge is small, and winners erase it. At -110 on both sides of a bet, a book that takes $110 on each side collects $220 and pays the winner $210, keeping $10, or 4.55%. A bettor at -110 needs to win 52.38% of the time just to break even.
A player who keeps getting better numbers than the market settles on is taking that 4.55% away. Kansas City opened at -7 against Miami for Sunday, September 27, 2026, and stood at -10.5 at DraftKings, as listed on ESPN on September 24. A bet on Kansas City -7 at the open holds a number three and a half points better than the one on offer now.
Buffalo is the same story in the same feed: -2.5 at the open, -7 by September 24. Bets that land on the right side of moves like these, again and again, are what the Massachusetts memo called beating the closing line, and what it tied to lower limits.
Other reasons in the rules
Other triggers are named in the terms themselves. William Hill’s UK terms list these among its “Prohibited Practices”:
- Promotion abuse: including “betting on all possible outcomes or opposite sides of an event.”
- Duplicate accounts: opening or colluding in more than one, including accounts at the same address, email or IP address.
- Inside information: betting in breach of a sports governing body’s rules, “including … misuse of inside information.”
- Exploiting errors: carrying on betting once it is apparent that a price or system error is occurring.
Two more rules reach beyond one account. William Hill says a restriction for a prohibited practice can be shared with “the other companies within our corporate group,” which may restrict their accounts too. Caesars’ Massachusetts rules say it may “investigate repetitive wagers made from a single account, or syndicate accounts, with the same outcome,” and void them pending the Commission’s approval.
Massachusetts now requires a reason
A rule in Massachusetts that took effect on June 1, 2026, requires sportsbooks to tell a bettor within 48 hours when an account is limited and to give a specific reason, according to CBS Sports and Gambling.com. Both report that the Gaming Commission approved it in December 2025, and Gambling.com reports the vote as 5-0.
It is a Massachusetts regulation, so it binds sportsbooks only there. CBS Sports describes it as the first of its kind in the United States, and Gambling.com reports that it also reaches limits placed before June 1.
What a limited player can do
Read the limit as information about your account. Outside Massachusetts, none of the clauses quoted above require the book to explain it, and in the Massachusetts data most limited accounts were cut to less than a quarter of the default bet.
Spread your action across more than one book, and keep records of the numbers you took against where lines closed; our guides to implied probability and calculating overrounds show the arithmetic behind the 4.55% above. For other places to bet, see our sportsbook reviews and pay-per-head reviews, and this week’s lines are on our NFL predictions hub.