StubHub is the largest secondary ticket company, and the second-largest overall ticket seller, according to TicketNews’s exclusive industry rankings. The company bills itself as the “world’s largest ticket marketplace,” where fans can buy and sell tickets sports, concert, theater and other live entertainment events.

The company’s customer base is vast, comprising tens of thousands of consumers and brokers. StubHub was launched in 2000, and while it didn’t invent the secondary ticket market, it has gone a long way to legitimize it. In 2007, the company was bought for $310 million by online auctions giant eBay (NASDAQ: EBAY), which already had its own secondary ticket marketplace.

Part of where StubHub succeeded most was by creating a “safe, convenient, and highly reliable environment” for buying and selling tickets, and the company used its strong reputation to secure a massive deal in 2007 with Major League Baseball to be the league’s official secondary ticket company. Every team, except the Boston Red Sox, uses the StubHub system.

On the legal front, the company has fought against Ticketmaster and the New England Patriots, both of which filed unrelated lawsuits against the company over ticket resale matters.

The company has formed partnerships with other major sports and entertainment entities, including the New York Yankees, Chicago Bears and the University of Southern California, Madonna, ESPN and American Express.