Well, the whole point of markets is to incorporate information into the price. So if I've done research and think company X is undervalued, I'm going to buy its stock, the price is going to go up, and now that research of mine is better incorporated into the stock price of X.
As long as I didn't _take_ that info from anyone (e.g. I can't hack emails, or bribe an accountant, etc. etc.), this is markets behaving exactly as we want them to.
Oh, okay. I think I see now. The stock market has always fascinated me and I admit I understand very little of it. I wouldn't know where to start learning about the ins and outs of it.
I'm short on good resources, but you might enjoy Matt Levine's Money Stuff newsletter; I always look forward to reading it, and all of this "what is insider trading" comes directly from his writing in recent weeks.
