“I do know from our work that big banks have confidentiality/NDA agreements with all of their vendors (and employees) which prevent them from voluntarily revealing any details about their engagements,” Mike Delikat, a partner at Orrick, Herrington & Sutcliffe told LawNewz.com."
http://lawnewz.com/uncategorized/why-we-will-likely-never-know-much-about-hillary-clintons-paid-wall-street-speeches/