Is sports betting rigged?
No, not in the way people mean. A book doesn't need to fix games, because the price already gives it the edge. What it does do is limit winners and move lines, and those feel rigged when you're on the wrong end of them.
The book's edge is in the price
Take an ordinary spread bet at -110 on both sides. You lay $110 to win $100, so to break even you need to win 52.4 percent of your bets. Pick at 50 percent over 100 bets and you're down $500, without anyone touching a game. If the book gets equal money on both sides, it keeps 4.5 percent of everything bet, whoever wins. That's the vig, and it's the whole business model (the how bookies make money page goes through it).
A book that rigged games would be taking a big risk to win money it already wins by arithmetic. I never met a bookie who needed to.
What feels rigged and isn't
Lines move against you. You bet the favorite at -3, the line goes to -4, and the dog covers anyway. That move came from money and news, not from someone who saw your ticket (why odds move explains it).
Winning players get limited. This one is real, and I won't defend it as fair to the player. A book that sees someone beating its closing numbers will cut the most he can bet, sometimes to a few dollars. It's a business decision about who the book wants as a customer, and the limits page covers how it works. The game wasn't fixed. The door just got smaller.
Parlays and props carry a bigger cut than straight bets. Nothing hidden there either: the margin is in the price if you work it out, and the no-vig calculator will do that for you.
Where the real risks are
Games do get fixed now and then, usually by a player, an official or someone close to them, and usually in smaller sports and lower leagues where the money involved is small enough to tempt someone. Leagues and regulated books watch for odd betting patterns, and unusual money on an obscure game is often how a case comes to light. That's a risk to the book as much as to you, because the book is the one paying the fixer's friends.
The bigger risk for most players is simpler: a book that doesn't pay. A slow-pay or no-pay shop doesn't need to rig anything. It just sits on your withdrawal. That's why I'd look at a book's payout record before its bonus, and why our offshore sportsbooks section reviews the places that take the money.
The math is against you on every bet. That's not a conspiracy, it's the price of the ticket.
Related questions
What is the vig?
The vig is the bookmaker's cut, built into the price. At the standard -110 you lay $110 to win $100, and that extra $10 is how the book gets paid.
Why do odds move?
Odds move because the book's risk changes or the information does. Money moves a line, most of all money from bettors the book respects. So do injuries, weather and what the other books are dealing.
How do bookies make money?
A bookie makes money by charging for every bet. The charge is built into the price: you lay $110 to win $100, and across thousands of bets that extra $10 is his living. He does not need to pick winners. He needs volume.