For a potential reader there must be some way to go back and see an authentic source you are referring to. I find no meaning in referring to something that only exists in a few minds, possibly with different interpretations for the same thing. Edit* As mentioned by @mkennedy in the comments below, it is possible to cite interview type communication as personal communication.
One way is to create a source, with due permission from the mentioned CEO and then cite it. If possible and everyone attended the meeting agrees; the minutes of the conference may be edited with an addendum stating why it is done so.