Alternatively, instead of disclosing on a huge delay, have them disclose instantly. We have the mechanisms to do this nowadays.
Even "ETFs" are a big enough hole to drive a truck through in terms of performance, e.g., it's not hard to guess how an oil ETF will perform in response to certain geopolitical events.
We could also apply Presidential rules to all of them. The President has to essentially forgo all ability to manage his or her wealth during the time they are in office. Such shenanigans as they play must either be to benefit someone else, or a very long term play for when they are out of office. This is still what you might call "suboptimal" but it's an improvement, even just the "longterm" part. (We should be so lucky as for our politicians to be thinking about how to goose the longterm performance of our economy rather than how to make a couple million next week no matter what it does to everyone else.)
I would say instead of just blanket "ETF":
1. Only things that approximately match the contents of TSP funds or broader
2. Have to write down a 10b5-1 for the entire duration of your election plus one year, with a double cooloff period (6mo vs 3mo), and have to extend it within 3mo of each successful election.
Or have them disclose before they buy?
Instant disclosure would allow ETFs, which is probably the best option.
I think having a congressional required fund that the public could also invest in makes sense as well.
I’ve been thinking about an act to intentionally enrich members of Congress for reducing the deficit (e.g. a fraction of percent of savings certified by GAO goes to district and to member’s fund with a multi year cool off period, saving based on ratcheted down watermark).
The first allows constituents to reap the benefits of their member’s power, the second incentivizes members to be as financially motivated to not spend money as they are to spend money.