Still a work in progress, but https://www.govtrades.com as a site to easily view stock returns of senators. The goal is to increase transparency of trades and accountability in policymaking as its becoming clearer that senators still leverage non-public information in trading and may be swayed in policymaking based on stocks they own.
There is a toggle for the S&P500 you can select, but definitely agree that this should show up as a default to make it clear.
One thing we've noticed is that most senators don't beat the S&P500, but the main reason seems to be that they simply have less risky portfolios (e.g. a lot of bond ETFs)
A great feature to add would be a weekly email, featuring the trades of the top performing senators over long term time horizons. That way users could copy their trades on the presumption it is either insider trading or expert advice.
Thanks for the suggestion, we're planning on starting that up soon. Give the newsletter a subscribe if you'd like to receive updates/summaries as soon as they start: https://www.govtrades.com/subscribe
There was another reply in this thread working on something similar; I'm sorry that I don't remember what it was, or where to find it in this haystack, but you might be able to dig it up if you're curious.
Totally, that should be up within the next couple days. You can check out the methodology section for more details, but the data comes from public disclosures mandated by the STOCK Act (and Yahoo Finance for stock prices).
You might feel even worse when you learn that she's faced continued losses since the Dotcom bubble. Almost all her stock holdings are of RealNetworks, a company she worked for in the 90s: https://en.wikipedia.org/wiki/Maria_Cantwell
(Edited to make link clickable)