Um, I know a guy that got fired for doing this at a bank we both worked at several year's ago.
I think the issue was that he bought it before it was made available to the public. I recall him telling me that he was told that it would have been okay if he had bought it at public auction or after it was on the market for a certain number of days.
Of course, this was about 1987, so .... grain of salt and all that.
Just another self-proclaimed expert ...