Nonprofit organizations are required to make their annual federal tax filing, the form 990, available to the general public as part of the requirements to preserve their nonprofit status. Some nonprofits post their 990 on their website; others will provide it “upon request”. But many no longer worry about providing access because they assume that Guidestar.org will take care of it.
Guidestar is a nonprofit itself, founded in the mid-90s as a resource for other nonprofits. They have several ongoing programs, all focused on collecting and analyzing data. One of their earliest programs is the most famous – creating a database of American federal tax filings. Currently they offer the last three years of federal filings. Organizations are encouraged to fill out additional information online to help create a fuller picture of the organization as a resource for potential funders.
Any nonprofit’s general organizational profile is readily viewable. However, in order to view the tax forms you must login to the site with a free account. You can sign up as a private individual – no need to currently be working at a nonprofit org yourself.