I heard over a decade ago how Congress was going to vote on a law that would prohibit them from insider trading, as they were privy to info that was illegal for any of the public to know. I don't know how the vote went, but if you look, that's how most of them made their millions, in stocks but with the added advantage of said info.
Even if they can no longer do so legally, that wont stop some of their pals from sharing such tips with them.