Because of DAFs this is de-facto very rarely a problem. At least as it currently stands money donated from a DAF counts 100% towards the public support test, so you just need to find a single substantial donor with a DAF to meet your public support requirements.
Open Phil does indeed facilitate some of their giving via DAF. Lightcone has had years where we would have at least gotten close to failing the public support test, but we just asked OP to make a grant via a DAF, and then we were totally in the green.
Because of DAFs this is de-facto very rarely a problem. At least as it currently stands money donated from a DAF counts 100% towards the public support test, so you just need to find a single substantial donor with a DAF to meet your public support requirements.
Does this fall apart for sufficiently large donors? Could OpenPhil do all their giving via a DAF?
Open Phil does indeed facilitate some of their giving via DAF. Lightcone has had years where we would have at least gotten close to failing the public support test, but we just asked OP to make a grant via a DAF, and then we were totally in the green.