[thayne]

It isn't necessarily that they have information the public doesn't (although it could be that, they would know about policy changes before the general public does). It could also be that they use their leadership position to push forward policies that benefit stocks that they own.

[fwip]

This could even happen for non-selfish reasons. If you genuinely believe that, e.g, "The future of America is BigTech," you'll both favor tech stocks in your portfolio and be more sympathetic to their lobbyists and favored bills.