During the California gold rush, the adage goes, savvy businessmen sold shovels. Some 150 years later, as prospectors sprint towards the multibillion dollar gusher that is the growing U.S. sports betting industry, startups are equipping bettors searching for profits with a new set of tools. Companies like OddsJam cater to-and look to grow-the number of gamblers who think of sportsbooks more as financial markets than an idle game.

OddsJam’s core feature tracks lines at dozens of sites to find the most favorable odds on each wager. The tool also highlights cases where one book’s odds are so favorable as to offer a positive expected return, assuming the rest of the market has accurately priced the bet.