 Members of Congress and their family members are supposed to disclose their trades within 45 days. Now there are funds you and I can invest in that use that information to mimic congressional trades. One ETF tracking the trades of congressional Democrats has gained 30% since it was started in February of last year, beating the S&P, according to Yahoo Finance. Eric Gordon, a professor at the University of Michigan Ross School of Business, looked at what's behind the success of congressional stock picking.