HNA bought the property -- a 28-story tower at 123 Mission St. -- for $255 million in August 2016.: (Bloomberg)—HNA Group Co. is in discussions to sell a San Francisco office building to private equity firm Gaw Capital Partners, according to a person with knowledge of the talks, as the Chinese conglomerate tries to shed billions of dollars in assets. Discussions are preliminary and there is no guarantee of any agreement, said the person, who asked not to be identified because the talks are confidential. HNA and Gaw Capital didn’t respond to requests for comment.