‘X’ on Twitter’s headquarters faces investigation over permit violations

An “X” sign installed on Twitter’s San Francisco headquarters on Friday as part of the company’s rebranding is under investigation by the city for lacking proper permits, according to officials.

“A building permit is required to make sure the sign is structurally sound and installed safely,” Patrick Hannan, a spokesperson for the San Francisco Department of Building Inspection said in a statement Sunday. “Planning review and approval is also necessary for the installation of this sign.”