What if you could invest in your favorite sports stars the way you invest in stocks? That's the premise behind the Boston-based startup StarStreet, where fans stake real money on players, buying and selling shares over the course of a season before cashing out when all the games are over.

The site launched a daily fantasy baseball game on Wednesday, continuing its expansion into the emerging space. StarStreet's season-long games have already gained it a fair amount of press attention and some big-name investors including Jarr Capital and Ron Conway's SV Angel. The startup is a graduate of TechStars' Boston incubator and has so far raised $250,000 in funding.

It currently has more than 5,000 users, a quarter of which are active daily, and recently won a quick-pitch trade show competition at MIT's Sloan Sports Analytics Conference.

StarStreet's innovative stock market-based approach works like this: Users are allowed to deposit up to $5,000 into an account, and attempt to buy low and sell high as players go on hot streaks and statistical slumps throughout a season. The game is zero-sum, so all the money put in gets paid out at the end. For the new daily baseball game (a basketball version was the first of its kind for the site and launched about a month ago), users assemble teams of players to be matched against another user's players. Players are bought with a fictional budget of $100,000.

Founder Jeremy Levine has high hopes for the daily baseball game after its basketball counterpart had a huge debut, doubling its users base on each of four consecutive days after launch.

"Daily games have exceeded all expectations for us," Levine told Mashable.

The still-emerging daily fantasy sports game is becoming a competitive space, with sites including DraftDay.com, founded by a former online poker savant, and FanDuel.com, leading the way by raising a whopping $7 million in investments.

With StarStreet's own daily games picking up momentum quickly and its unique season-long investment model already in place, Levine believes it's in a good position to continue carving out its own niche. How exactly its two games balance out remains to be seen, but Levine says the combination provides something for everyone.

"I think it's tough to say, but it's going to be a mix of both," he says. "The longterm stock market game is its own thing, and the daily game is instant gratification."

Do you think a fantasy stock market where users invest in athletes is a cool idea? Let us know in the comments.

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