I'm not sure if there's any history of financial association, but I do know that all of these people generally travel in the same circles.

When I went to college in Berkeley I went to a couple rationalism adjacent events in the city and saw there was a huge overlap of that EA/Rationalism/Silicon Valley startups people. Never saw Sam Altman at those, but met a couple YC founders and other people who knew him and spoke generally well of him.

Lesswrong is ground zero for AI doomers, so this is right in their wheelhouse.

Less wrong is created by Eliezer Yudkowsky. Someone who is very outspoken against AI development, because of the fears around AI destroying humanity. Once went as far as calling for the bombing of AI researchers and/or data centers, if I remember correctly.

AI is one of the primary topics on LessWrong.

AGI x-risk was popularized there, it was always an attractor for the new AI alignment field