With Twitter surging on its first day of trading, there are lots of people who are suddenly #filthyrich.
Union Square Ventures was one of Twitter's earliest investors. Partner Fred Wilson, who writes the popular blog, A VC, was a vocal supporter from the start. The New York-based fund has invested in a number of social startups, including Foursquare and Tumblr. Wilson stepped down from Twitter's board in 2011.
Union Square is one of Twitter's largest institutional investors, with a 5.9% stake.