From what I've seen in headlines he buys a lot of big tech call options dated a year out or more. Since big tech has done well over the past decade, he probably has beat S&P by buying calls. As long as big tech stocks go up 10% a yr, he'll do well with that strategy.

According to this they invest heavy in mostly big tech, probably similar to a lot of people here https://housestockwatcher.com/summary_by_rep/Hon.%20Nancy%20...

I think the public should be given notice immediately when Congress members purchase or sell shares/options. I think they should also have to hold on to shares/options for a certain length of time. I think this could solve most problems.