The reindeer outperformed the S&P 500 by 4.9% in a single month. For comparison, the researchers analyzed stock picks made by members of the U.S. Senate and House of Representatives, and they underperformed the S&P 500 by 1.6% over the course of three months.  Some of the same researchers who conducted this holiday-inspired study had analyzed members of Congress’s stock trades in the spring, out of concern legislators were making moves based on confidential information gleaned from their committee assignments. (The researchers published those findings in an April paper titled “Relief Rally: Senators as Feckless as the Rest of Us at Stock Picking.”) The results indicate how hard it is—for humans, anyway—to outsmart the market, according to the study’s co-author Bruce I. Sacerdote, an economics professor at Dartmouth. “Contrary to what some people may think, U.S. Senators and House members have pretty limited stock-picking prowess but Santa’s reindeer seem to have a real knack for it,” said Sacerdote in a statement. “The strong performance of the reindeer portfolio could be due to luck, insight, or the magic of the season.”