Jack Dorsey has to choose between Twitter and Square Inc., a Twitter shareholder says in a Court of Chancery lawsuit.

CEO of Twitter Jack Dorsey. Frederic Legrand – COMEO/Shutterstock.com

The complaint filed Monday by attorney P. Bradford deLeeuw and with Berman Tabacco attorneys of counsel accuses Dorsey, who is CEO of both companies, of giving Square and other advertisers access to data Twitter users thought was private with the aim of generating revenue for both Twitter and Square.