Over 700 finance terms, Shmooped to perfection.
In determining whether or not you have inside information which would preclude you from making a trade, you have to determine whether or not the information you stumbled upon was material - or worth anything. You're standing in a Manhattan elevator and you overhear the CEO's doorman say, "His chief competitor has been here every night the last 3 nights for poker. I bet they are merging. Both stocks should go up a ton." That's almost certainly not material. But if the CEO's wife is standing there with the doorman and nods slowly after he utters this hypothesis, then it's almost certainly material and you can't trade in either stock.