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The NFL regular season starts Wednesday night, beginning a busy stretch for U.S. sports bettors.
Twenty-seven percent of Americans now have an active online sportsbook account, up from 19% in 2024, according to a Siena Research Institute survey of 3,084 people conducted Feb.16 – 27. The survey conducted by the non-partisan polling organization has a “credibility interval” of plus or minus 1.9 percentage points.
But as more people place bets online, some may take sportsbook rules lightly without realizing that violating them can have consequences for their bets or accounts, experts tell CNBC Make It.
Those rules can govern where you can place a bet, who can place it and even how you fund your account. And prediction markets are adding another wrinkle, offering sports contracts that can look like traditional bets but follow different rules.
Here are some things that experts say bettors should know.
You can’t have someone else place your bets
Bill Simmons, a podcaster and founder of the sports and pop culture site The Ringer, is a recent high-profile example of what can happen when someone else uses your sportsbook account.
On an Aug. 30 episode of “The Bill Simmons Podcast,” he described directing his daughter’s boyfriend to place wagers on his behalf in Massachusetts using Simmons’ account at online sportsbook FanDuel. Simmons resides in California, where online sports betting isn’t legal.
FanDuel later voided the wagers, took action on Simmons’ account and reported the matter to the Massachusetts Gaming Commission, a company spokesperson tells CNBC Make It.
Simmons later said he “did not know about the proxy rules” and had thought the practice was allowed.
“Many casual bettors do not realize that letting a spouse or friend place a bet for them breaks the rules,” says Eric Chaffee, a Case Western Reserve University law professor who studies sports betting regulation.
Known as proxy betting, placing a wager on someone else’s behalf is prohibited because it can be used to circumvent state-specific gambling rules. Violating those rules can lead to account suspension and forfeited winnings, Chaffee says.
Sportsbooks also place restrictions on how accounts can be funded. FanDuel told CNBC Make It that it monitors deposits and rejects payment methods when the name doesn’t match the account holder. The company also suspends the account while it reviews the activity for potential fraud.
Where you are matters — ‘not where you live’
Having a sportsbook account in a state where online sports betting is legal doesn’t mean you can use it everywhere.
“This is about where you are, not where you live,” Chaffee says.
Sportsbooks are required to verify that a bettor is physically present in a jurisdiction where they are allowed to accept a wager. That means someone can place bets through an app in one state, cross a state line and find that new wagers are blocked, says Ross Weingarten, a former federal prosecutor who co-chairs the Sports Integrity Team at law firm Steptoe.
GeoComply, which provides geolocation technology to major sports betting platforms including FanDuel, says its technology checks hundreds of signals to verify a bettor’s location and can recheck a device during a betting session, including when someone appears to be traveling or is near a state border.
Major sportsbooks typically still allow customers to withdraw funds in states where betting is prohibited or limited, even though they can’t place new bets, Weingarten says. However, if a sportsbook thinks a user is trying to get around state gambling restrictions, the company can freeze accounts and void winnings.
A VPN can interfere with location checks
VPNs are commonly used for work and privacy, but they can create an unexpected problem for sports bettors.
Because a virtual private network, or VPN, can disguise a user’s location, a sportsbook may not be able to verify where a bettor actually is. That means even someone physically located in a state where online sports betting is legal may be blocked from placing a wager while a VPN is running.
GeoComply says an active VPN isn’t inherently suspicious. In many cases, a customer has simply forgotten that a work or personal VPN is running and will be instructed to disable it and try again.
However, repeated or deliberate attempts to conceal or falsify a bettor’s location are treated differently. That activity may be flagged for additional review and, depending on the circumstances and sportsbook’s policies, could lead to account restrictions, suspension or closure, GeoComply says.
Sports bets don’t all operate under the same rulebook
Sports prediction markets like Kalshi and Polymarket can look like traditional sportsbooks, but they operate under a different legal framework.
While sportsbooks take wagers under state gaming licenses, prediction markets operate as exchanges where customers buy and sell event contracts with other traders, Chaffee says.
Prediction markets are federally regulated, but a growing number of states are challenging whether they should also be subject to state gambling laws. The different rules can affect who can use the platforms, where they can trade and what determines whether they make or lose money.
Most sportsbooks require customers to be at least 21, while Kalshi allows customers 18 and older. Prediction markets are also available in some states where traditional sports betting is illegal, Chaffee says. Customers still have to verify their identities, however.
It’s also important to read the terms of individual contracts carefully, Chaffee says. Those terms determine exactly what has to happen for a contract to pay out, including what happens if a game is postponed or doesn’t take place by a specified date. Misunderstanding them can mean being right about what happens on the field but still losing money on the contract.
Disclosure: CNBC and Kalshi have a commercial relationship that includes customer acquisition and a minority investment.
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