Executive officers and directors:

Evan Williams 56,909,847 shares, or 12 percent. Williams was Twitter's CEO until 2010, when current CEO Dick Costolo took the helm. He is now working on a publishing platform, Medium, which is dedicated to long-form content.

Benchmark 31,568,740 shares, or 6.7 percent. Venture firm Benchmark started investing in Twitter in 2009 when it was valued in the $200 million-$250 million range. This stake includes shares owned by partner Peter Fenton, who led the firm's investment in consumer-Internet play Yelp, holds a board seat at Twitter.

Jack Dorsey 23,411,350 shares, or 4.9 percent. Dorsey co-founded Twitter and still serves as its chairman. In 2009, he founded payments service Square and serves as its CEO.

Dick Costolo 7,589,608 shares, or 1.6 percent. A onetime improvisational comedian, Costolo took the helm of Twitter in 2010. He joined Twitter as COO the year before, after he and co-founders sold their web feed management provider FeedBurner to Google in 2007.

Adam Bain, 1,722,350 shares, or less than 1 percent. Bain is the president of global revenue at Twitter. He was formerly the president of audience network at News Corp's Fox Interactive Media.

David Rosenblatt, 283,333 shares, or less than 1 percent. Rosenblatt is the CEO of luxury online retailer 1stdibs.com and is a member of Twitter's board of directors.

The following groups own at least 5 percent:

Rizvi Traverse Management. A closely held private-equity fund based in Michigan, Rizvi has made a name for itself by buying stakes in entertainment companies such as Playboy and movie producer Summit Entertainment. Last year, it led a $200 million funding round in Jack Dorsey's payments company, Square.

Spark Capital. Venture firm Spark started investing in Twitter in 2008. For a time, Spark partner Bijan Sabet served on Twitter's board.

Union Square Ventures. Venture firm Union Square started investing in Twitter in 2008. For a time, USV partner Fred Wilson served on Twitter's board.

DST Global. The investment firm founded by Russian billionaire Yuri Milner led a $400 million investment in Twitter in 2011. At the time, Twitter was valued at around $8 billion.

(Editing by Bob Burgdorfer)

By Sarah McBride