It came out in the press recently that members of Congress were excluded from regulations barring insider trading, which, in turn, led to the passage of the recent STOCK Act to change the situation.
But two great recent investigative pieces from the Washington Post show that shady dealing goes well beyond anything that would be covered by insider trading statutes as such. For starters, members of Congress are free to profit off their own legislative activities:
Sen. Tom Coburn (R-Okla.) reported buying $25,000 in bonds in a genetic-technology company around the time that he released a hold on legislation the firm supported. Rep. Ed Whitfield (R-Ky.) sold between $50,000 and $100,000 in General Electric stock shortly before a Republican filibuster killed legislation sought by the company. The family of Rep. Michael McCaul (R-Tex.) bought between $286,000 and $690,000 in a high-tech company interested in a bill under his committee’s jurisdiction.
The second piece doesn't have any smoking guns that are quite that good but deals with members' habit of making large financial moves right after receiving briefings from Treasury and Fed officials.