Years ago I read about the idea of investing in companies who lobby Congress, since those companies outperformed other stocks. Perhaps by tilting the playing field, or perhaps by having enough money to lobby Congress. But there was a very narrow range of discussion where that remained an investing discussion, so I've avoided mentioning it since.
I'm not aware of a thorough study of members of Congress and investments. I'm aware in 2020, members of Congress dumped their stock holdings after being briefed on the Covid pandemic in February 2020. Technically, people could have figured out Covid would hit the U.S. and be bad (like I did), but having a panel of experts brief members of Congress is a decided advantage not available to most investors. But I'm not aware of a systemic study, only of isolated incidents (which others mentioned earlier).
You're in luck, because I posted one above!
"Do senators and house members beat the stock market? Evidence from the STOCK Act"
published in Journal of Public Economics in 2022.
(spoiler alert: no)
This looked at congress member trades from 2012 - 2020, so an actually slightly more meaningfully long period, rather than the 2 months before the pandemic (which as you point as was public information anyway!)
This paper also analyze congress member traders (2004-2022, but doesn't evaluate their performance, just note that they "trade more during crisis/uncertainty". To me they sound like your regular, think-they-are-smarter (underperforming) daytrader bro.
https://www.sciencedirect.com/science/article/abs/pii/S1059056024005835
Yeah, I truly can't imagine politicians magically having superior investing strategies on average.
I mean, sure, they have some insight and influence on *some* industries, but not beyond what industry insiders already have. Politicians are largely reactive creatures, so experts researching industries usually already have a pretty solid grasp of what to expect from them, which means a lot of what they do gets baked into share prices before they even do it.
Knowing more than the average person doesn't help much in trying to beat the market, you have to know more than the people who make entire careers of understanding industries and making bets on what they predict will happen, and that very much includes what politicians are likely to do.
It's also surprisingly difficult to know enough to have an advantage without commiting a crime, but even if politicians are ubiquitously committing insider trading crimes, it's still pretty useless to know what they are invested in if you didn't know *before* they bought it.