Another Form of Senate Corruption?

Through a link by Glen Reynolds at Instapundit, I found Professor Bainbridge making an observation about Congress:

So it seems that we are ruled by crooks and cheats.

Hmm, wonder where that idea comes from? The stage is set by:

Taken together, the semi-strong and strong forms of the Efficient Capital Markets Hypothesis teach that no class of investors can beat the market over time without routine access to material nonpublic information. Many studies have shown that the only investors who, as a class, routinely produce postive abnormal returns are corporate insiders. . . .

You see Professor Bainbridge was commenting on a report in the Wall Street Journal about recent research that discovered something interesting about the investment savvy of members of the US. Senate:

A study suggests that U.S. senators possess stock-picking skills that even the most seasoned money manager would envy. During the boom years of the 1990s, senators' stock picks beat the market by 12 percentage points a year on average, according to the study. Corporate insiders, meanwhile, beat the market by about six percentage points a year, while U.S. households underperformed the market by 1.4 percentage points a year on average, according to separate studies. The final details of the study will be published in the December issue of the Journal of Financial and Quantitative Analysis. ...

Looking at the timing of cumulative returns, the senators also appeared to know exactly when to buy or sell their holdings. Senators would buy stocks just before the shares suddenly would outperform the market by more than 25%. Conversely, senators would sell stocks that had been beating the market by about 25% for the past year just when the shares would fall back in line with the market's performance.

Imagine that, eh? Senators just seemed to know when a stock outperforming the market would be best sold. Could be a little bird whispers in their ears, eh?