Two U.S. senators who sold stocks just before the March market crash, having received information about the severity of the pandemic that the public didn’t possess, have drawn widespread criticism.

But a new academic paper shows that senators’ trades — both purchases and sales — of stocks mostly underperform the broader market. What’s more, the researchers find that senators’ committee assignments don’t help them realize greater returns on trades in related industries. “Perhaps not surprisingly, we find only limited evidence that senators display stock-picking prowess,” the paper concludes.

In the paper, “Relief Rally: Senators as Feckless as the Rest of Us At Stock Picking,” the researchers — an economics professor and two students at Dartmouth College — focus on stock trading starting in 2012, after the passage of a law meant to curtail insider trading by government officials.

Past research has showed that before the legislation, known as the STOCK Act, portfolios held by senators did better than the broader market nearly 1% per month.

“The literature supports the hypothesis that prior to the passage of the STOCK Act members of Congress were leveraging their privileged positions in order to achieve superior financial returns,” the Dartmouth researchers wrote.

To some extent, the STOCK Act has had an impact: In the three years leading up to its passage, there were 7,582 financial transactions with a maximum transaction value of $1,495,559,000 by senators. In 2015, three years after the legislation was enacted, a researcher counted 2,475 transactions with a maximum transaction value of $337,480,000.

Related:More evidence that passive fund management beats active

The new research, by the Dartmouth team, examines trades from 2012 to March 2020 — that is, post–STOCK Act, but including some of the recent trades that seemed to stem from privileged information relating to COVID-19.

Senators’ stock purchases lag the benchmark at six-month intervals by 17 basis points. They also underperform at shorter intervals, but the researchers note that only the six-month horizon is statistically significant. Stocks sold also underperform “insignificantly” at the six-month level and outperform, by 14 basis points, one year later.

With that in mind, the researchers do note that the recent trading that sparked a furor “showed both a market timing and a stock picking component; sales outnumbered buys by 2 [to] 1 and the stocks sold underperformed the market by 9%.”

Read:Two senators under scrutiny over selling stock before the coronavirus market crash — but do insider-trading laws apply?

Still, not much time has lapsed since that trading took place: Republican Sen. Richard Burr of North Carolina sold hundreds of thousands of dollars of stock in mid-February, while Sen. Kelly Loeffler, appointed to an open Senate seat by Georgia’s Republican governor late last year, made trades in February, including purchases of Citrix Systems Inc. CTXS, +0.03% , a company whose software enables remote work. Loeffler’s husband, Jeffrey Sprecher, is CEO of Intercontinental Exchange Inc. ICE, -0.75% , the operator of the New York Stock Exchange.

For what it’s worth, the Dartmouth researchers also broke out their analysis by political party, writing, “The data suggest that Democrats may have some slight skill in picking stocks to buy while Republicans are skilled at picking stocks to sell. However, this conclusion is tempered by the fact that Republican purchases underperform by as much as Republican sales. A more accurate description of the results is that, on an industry-size adjusted basis, Republicans pick stocks that do somewhat poorly when bought and even after when sold.”

Whether or not government officials beat the market may be beside the point, however, as the researchers themselves acknowledge. The STOCK Act has been somewhat neutered since it was passed in 2012, but at the time of its passage it was “seen as a pivotal step in addressing public skepticism about an unequal system. As President Barack Obama put it, the STOCK Act was meant to “address a ‘deficit of trust’ between the American people and their lawmakers.”

As Columbia Law School professor John Coffee told MarketWatch reporter Andrew Keshner last month, “We’ve got this coronavirus national crisis. It’s had everything except a classic Hollywood villain.”

Federal lawmakers trading on information “are going to look like the worst villain we seen in this story,” Coffee said.

See:Fannie and Freddie stock moves may be insider trading, watchdog groups suggest