So you want to be a fiscal sponsor or find one for yourself?
I have culled what I think are the best, most easily understood sources to get you started on the right track. They are all short, so I encourage you to read them all
First, a couple definitions from the National Council of Nonprofits:
What does a fiscal sponsor do? Agrees to accept the administrative and fiduciary responsibilities of receiving charitable gifts on behalf of the sponsee
The Sponsored Project/Organization ("sponsee"):
Finds a nonprofit to serve as its fiscal sponsor
Provides whatever records/reports it agrees to in its written sponsor agreement
The Sponsor:
Affirmatively decides that serving as a fiscal sponsor is consistent with its mission
Receives donations (not the sponsee), sends acknowledgments to donors, and grants the dollars to the sponsee
Acts as fiduciary for the contributions made in all the ways it would its own, including reporting the income and expenses as its own (i.e., IRS Form 990)
Next, go-to sources to learn how to do it correctly:
National Network of Fiscal Sponsors: Sponsee Responsibilities & Myths About...
Gregory Colvin, author of THE book: 15 Questions to Ask & Agency v. Sponsorship
Propel Nonprofits: A Board’s Guide to Fiscal Sponsorship & 3-min Video Primer
Fractured Atlas: They have a detailed program and HERE is their agreement
Go forth. Do good. Be well.