Back in 2007, Eric Lefkofsky and Brad Keywell invested in a struggling Internet startup, Groupon.

FORBES: Lightbank: A Talk With Groupon's VC Backer

Last year, the co-founder of Groupon ( NASDAQ:GRPN), Brad Keywell, gave a keynote speech.

FORBES: Groupon's Accounting Mistake, the Media, Quant Funds and Academic Case Studies

According to the filing, cofounder Bradley Keywell owns 6.9% of class A and 16.7% of class B shares.

FORBES: The Groupon IPO: By The Numbers

At least he has company, as Groupon investor Bradley Keywell fell out of the ranks with equal speed.

FORBES: Easy Come, Easy Go: Groupon's Chief No Longer A Billionaire

He and Keywell founded Lightbank, which is based in the same building as Groupon, in 2010 and have since invested in more than 20 startups, the bulk of which are based in Chicago.

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