If you're asking me for some of my property (money) as an investment to improve your property (the company) with the intent that my property will be converted into a share of your property, but you secretly know that your property is about to lose its value and you don't tell me, but you do tell others who have previously invested to get out while still telling me to get in, then you are dealining in insider trading, which is also fraud (a fraud of omission to the outsiders).
The fact that some people in some situations have some information that some other people don't have -- that does nothing to erode anyone's "trust" in the market.
The "information" is your intent to take certain actions, or your knowledge of someone else's intent to take actions, or actions already taken but unknown to most, not a rumor heard on the street.
-PJ