501(c)(4) social welfare organizations do not have to disclose their donors, either to the IRS or to the public, under current federal rules. Since 2018, these groups have stopped reporting contributor names and addresses on their annual tax returns, and the statute governing public inspection of exempt-organization filings shields donor identities from anyone requesting a copy. The main exception is political spending: when a 501(c)(4) pays for certain campaign-related communications, Federal Election Commission rules can force it to name the people who funded that activity.
What the IRS Collects From a 501(c)(4)
Every 501(c)(4) with annual gross receipts normally above $50,000 files Form 990 or Form 990-EZ, reporting revenue, expenses, compensation, and governance.1Internal Revenue Service. Annual Electronic Notice (Form 990-N) for Small Organizations FAQs: Who Must File Smaller organizations file the Form 990-N e-Postcard, which asks only for basic identifying information.
Form 990 includes Schedule B, historically used to list contributors who gave $5,000 or more. In 2018, the IRS issued Revenue Procedure 2018-38, which eliminated the requirement for tax-exempt organizations other than 501(c)(3) charities to report contributor names and addresses on Schedule B. The change applies to tax years ending on or after December 31, 2018, and the IRS explained that collecting the names was not necessary for tax administration.2Internal Revenue Service. Revenue Procedure 2018-38
A 501(c)(4) still files Schedule B and still reports the amount of each large contribution and whether it was cash or property. It enters “N/A” where the donor’s name and address would go.3Internal Revenue Service. Instructions for Schedule B (Form 990) The IRS gets the financial picture. It does not get the names.
What the Public Can See
Federal law requires exempt organizations to make their Form 990 available for public inspection at their principal office and on request, and nonprofit databases post the filings online.4Office of the Law Revision Counsel. 26 USC 6104 – Publicity of Information Required From Certain Exempt Organizations and Certain Trusts Anyone can review revenue, expenses, executive pay, and the board roster.
The same statute exempts organizations other than private foundations and political organizations from public disclosure of donor identities.4Office of the Law Revision Counsel. 26 USC 6104 – Publicity of Information Required From Certain Exempt Organizations and Certain Trusts So a member of the public can see that a 501(c)(4) took in a particular amount, but not who wrote the checks. That combination — no names to the IRS, no names to the public — is why money moving through 501(c)(4)s is often described as dark money, particularly when the group runs political ads.
When Political Spending Forces Names Into the Open
A 501(c)(4) is allowed to engage in political activity so long as that is not its primary purpose.5Internal Revenue Service. Social Welfare Organizations Once its spending crosses certain lines drawn by the Federal Election Commission, though, disclosure rules take over and can reach individual contributors.
Independent Expenditures
An independent expenditure is spending on a communication that expressly advocates the election or defeat of a clearly identified candidate, made without coordinating with the candidate.6Federal Election Commission. Understanding Independent Expenditures If a person or organization that is not a political committee spends more than $250 on independent expenditures in connection with a given election in a calendar year, it must report on FEC Form 5.7Federal Election Commission. Instructions for Preparing FEC Form 5 Those reports itemize each contributor who gave more than $200 for the purpose of furthering the independent expenditure.
Electioneering Communications
Electioneering communications are broadcast, cable, or satellite ads that name a federal candidate and air shortly before an election.8Federal Election Commission. Making Independent Expenditures A 501(c)(4) that spends more than $10,000 in a calendar year on these communications files a statement on FEC Form 9 listing the names and addresses of each contributor who gave $1,000 or more, aggregated from the start of the preceding calendar year.9eCFR. 11 CFR 104.20 – Reporting Electioneering Communications
The Earmarking Question
Both FEC disclosure rules hinge on the purpose of the contribution, not just what the organization later does with the money. A donor who gives to a 501(c)(4)’s general fund without earmarking the gift for a political ad typically remains anonymous, even if the group later draws on general funds to pay for political spending. That distinction is why so much political money runs through 501(c)(4)s in the first place: donors who avoid earmarking their gifts stay off the FEC filings.
What States Can Require
Before 2021, several states required 501(c)(4) organizations that solicited donations within their borders to hand over unredacted copies of Schedule B, with donor names attached, as part of charitable registration. State attorneys general defended the practice as a fraud-monitoring tool.
In Americans for Prosperity Foundation v. Bonta, decided July 1, 2021, the Supreme Court struck down California’s version of that requirement. Applying “exacting scrutiny,” the Court held that a government demand for donor lists must be narrowly tailored to an important interest, and it found California’s blanket collection failed the test because the state could not show it actually used the information for the fraud investigations it claimed to run. The Court held the requirement “facially unconstitutional” as an undue burden on donors’ First Amendment associational rights.10Supreme Court of the United States. Americans for Prosperity Foundation v. Bonta, 594 U.S. 595 (2021)
After that ruling, states cannot demand routine donor disclosure from 501(c)(4)s for general oversight. Most now accept redacted filings that match what the organization sends the IRS. A state could still seek donor information in a targeted investigation, but the era of collecting full donor lists as a registration condition is over.
What the Organization Still Has to Keep
Not reporting donor names is not the same as not tracking them. The IRS requires every exempt organization to keep books and records sufficient to document the sources of its receipts and its expenditures, and to produce those records if the return is examined.11Internal Revenue Service. EO Operational Requirements: Recordkeeping Requirements for Exempt Organizations The general three-year statute of limitations on tax assessment sets a practical floor for how long a 501(c)(4) should hold onto donor records, and the recordkeeping obligation applies even to organizations small enough to file only the Form 990-N e-Postcard.
So the accurate picture is narrower than “501(c)(4) donors are secret.” The IRS can obtain donor identities through an examination. The FEC can obtain them when contributions fund covered political activity. The public, absent one of those triggers, cannot.