Historically, such non-profits have not been required to disclose their donors or names of members.

Spending by organizations that do not disclose their donors has increased from less than $5.2 million in 2006 to well over $300 million in the 2012 election.

Interested in maintaining their privacy, they prefer to spend on donations to non-profit groups who do not disclose donors.

This has led to claims of large secret donations, and questions about whether such groups should be required to disclose their donors.

It must also state that contributions to the organization are not deductible as charitable contributions during fundraising. 501(c) (4) organizations are not required to disclose their donors publicly.