The Wikipedia entry for Albert Grossman includes the following info:
"The group had been avidly pursued by Atlantic Records, who were on the verge of signing them when the deal inexplicably fell through. The group signed with Warner Bros. Records instead and Atlantic's executives later discovered that it was because music publisher Artie Mogull had introduced Grossman to Warner executive Herman Starr, from whom Grossman was able to extract an unprecedented deal that gave the trio complete creative control over the recording and packaging of their music."
Reference is made to this book:
Fred Goodman, Mansion on the Hill: Dylan, Young, Geffen, Springsteen, and the Head-On Collision of Rock and Commerce (Random House, 1998), pp.88-90