5. Fred Wilson

Missed Funding in: Airbnb

Fred has denied investment to many companies like Pandora, Groupon and Bump. But, the investment that he missed and regrets most is Airbnb, when they had paid a visit to his company in 2009. "We couldn't wrap our heads around air mattresses on the living room floors as the next hotel room and did not chase the deal. Others saw the amazing team that we saw, funded them, and the rest is history. Airbnb is well on its way to building the eBay of spaces," co-founder of Union Square ventures told Business Insider.