Twitter, Zynga and Yelp have all reportedly suggested that a move outside of San Francisco might make better financial sense, as they add new employees and gear up for possible IPOs. The ad-hoc advisory council will "recommend new policies related to high-growth technology companies," and "evaluate how San Francisco's current tax structure impacts companies' ability to successfully grow jobs in San Francisco," city officials said. Mayor Edwin Lee, Board of Supervisors President David Chiu and Supervisors Ross Mirkarimi and Mark Farrell issued the statement.