My guess is that you can purchase the most x-risk reduction by donating to either SI or FHI; the other orgs either don't exist yet or don't have much of a track record yet.
SI and FHI already coordinate with each other quite a bit. Leverage Research is composed of people who have significant contact with SI or were past visiting fellows/employees of SI.
For now, I won't say more than that.
Thanks - that fits with the general impression I've got.
I somehow missed the post on Leverage Research. I'd heard of them before but was put off by Connection Theory and all those flowcharts.
Of course: FHI, FutureTech, the Singularity Institute, and Leverage Research.
New: the Global Catastrophic Risk Institute (Seth Baum & Tony Barrett).
I've also heard that the following people are working to set up x-risk departments/organizations:
Huw Price at Cambridge
Newton Howard at MIT
Jeffrey Epstein