So the question is: is all this legal? While there’s some difference of opinion on the issue among law professors, the proper answer to that question is most likely going to be, “Yes, it’s legal.” As UCLA’s Stephen Bainbridge points out, existing insider trading law, developed by way of a long series of contested cases under the Securities and Exchange Commission’s Rule 10b-5, assigns liability to persons who are not corporate insiders if they are violating a recognized duty of loyalty to those for whom they work. As applied to the investment whizzes of the Hill, this implies that trading on inside information might be a violation if done by Congressional staffers (since they owe a duty of loyalty to higher-ups) but not when done by members of Congress themselves.
Read more: Congressional Insider Trading: Is It Legal? — Cato at Liberty