Winning bets are paid when the event finishes, or if not finished, when played long enough to become official; otherwise all bets are returned. This policy can cause some confusion since there can be a difference between what the sportsbook considers official and what the sports league consider official. Customers should carefully read the sportsbook rules before placing their bets.

The betting volume at sportsbooks varies throughout the year. Bettors have more interest in certain types of sports and increase the money wagered when those sports are in season. Likewise the interest in sports varies by country since the level of interest in the various sports is not constant throughout the world. Some major sporting events that don't follow a specific schedule, like boxing, can create peaks of activity for the sportsbooks.

Word origin

A sportsbook is a portmanteau, combining two words into one word with a new meaning: a sports gambling operation. In this case "sports" and "book" which is short for bookmaking.

Odds

In the mid 1930s, Leo Hirschfield started a company in Minneapolis, Minnesota called Athletic Publications, Inc., that published and distributed odds to bookies across the country by telephone and telegraph. He had a team of handicappers analyzing the matchups who also studied newspapers across the country. The company was a major provider of odds and prices until it finally disbanded, under fear of prosecution from the Federal Wire Act of 1961.

Today most sportsbooks get their opening prices from other sportsbooks as well as private companies like Las Vegas Sports Consultants. They adjust prices based on the bets coming in, news, injury, and weather information, and the price movement by other sportsbooks.

Nevada sportsbooks

Today there are roughly 150 licensed sportsbooks in the United States, all located in Nevada casinos. Now that many casinos share the same parent company, they offer the exact same wagering choices and odds, which is a disadvantage to the astute gambler who in the past could do more shopping for better prices.

In the 1950s the first Nevada sportsbooks, called Turf Clubs, opened. They were independent from the casinos, and had an informal agreement with the hotels that they would stay out of the casino business as long as the hotels stayed out of the sportsbook business. The sportsbooks had to pay a 10 percent tax so they charged a high vigorish to gamblers, but they still brought in a lot of business.

In 1974 the tax was lowered to 2 percent, (it was lowered to 0.25 percent in 1983), and in 1975 Frank Rosenthal, who ran the Stardust Casino, convinced legislators to allow them in the casinos, and soon nearly all of the casinos added them. The turf clubs were no longer able to compete and eventually all closed.