Ken Vogel, NYT: Hillary Clinton only learned of the dossier when BuzzFeed published it
https://www.nytimes.com/2017/10/25/us/politics/steele-dossier-trump-expained.html
Who else knew about Mr. Steeles research during the campaign?
Officials from the Clinton campaign and the D.N.C. have said they were unaware that Perkins Coie facilitated the research on their behalf, even though the law firm was using their money to pay for it. Even Mrs. Clinton only found about Mr. Steeles research after Buzzfeed published the dossier, according to two associates who discussed the matter with her. They said that she was disappointed that the research as well as the fact that the F.B.I. was looking into connections between Mr. Trumps associates and Russia was not made public before Election Day.
But word of the memos and their contents had circulated in Washington political and media circles before the election. In British court filings, Mr. Steeles lawyers said that he and Fusion GPS briefed journalists from a range of media outlets, including The New York Times, on his research starting in September of 2016.
Yet the research and even the existence of the dossier were not reported by the media, with the exception of Mother Jones magazine, which published a story in the days before the election that described the dossier, its origin and significance, while omitting the salacious claims.