The prohibition against insider trading is against trading while in the possession of material, non-public information. So there are two things you can do. You can wait for it to become not material, or you can wait for it (or cause it) to become public.
How does something become not material? When superceding events intervene. Let’s suppose you have come into possession of a company’s non-public business projections for the first quarter of 2004. Furter suppose that these projections are different from the analyst guidance projections. After the company reports the first quarter, whether they met the projections you have or not, your information is stale and you may trade freely. If you learn that Amalgamated Widget is going to make a bid for the company, the information becomes stale if they change their mind. (NOTE: Don’t do either of these things without talking to a lawyer – the examples are stupefyingly simplified!)
What about public? Well, you can’t just put out a press release and be done with it. The information must be public and widely disseminated. What the heck does that mean? There’s no objective standard, but generally speaking it means disseminated in a way that a reasonably diligent potential trader in a company’s securities would have access to it. The most bulletproof place is in SEC filings, especially since they’re now available online. If you’re a company’s CEO, you can cause the company to file an 8-K announcing to the world whatever the information is, and following that you can trade.
You can also make it public via press release, but you can’t write your own, fax it to the Wall St. Journal and be done with it. Someone has to actually publish the release. So say the Journal picks it up on its wire service – you’re good. There are also large, professional press release services such as Businesswire and PRNewswire. Most observers believe that sufficiently many investors follow those companies’ press releases that using them is sufficient to acheive “dissemination” even if no independent source picks up the story. But not all observers.
Also, keep in mind that you may be prohibited from making information public by other restrictions – confidentiality agreements, fiduciary duties, privacy laws, etc. So this avenue is not available to everyone or in all cases.
Here’s the basic smell test: If the information you have would make a reasonable person make a different judgement about a security’s value and that person doesn’t have access to the information, you’re restricted.
It’s important to realize is that insider trading is very, very rarely litigated. Most cases are settled. So there is little case law as to what, specifically, insider trading is.