A tax-exempt organization that files a Form 990 tax information return must make it available to the public upon request, but a 501(c)(3) charity may keep confidential the names of donors on Schedule B. (See Ready Reference Page: "Tax Exempts Must Provide Applications, Returns.") The penalty is $20 a day with a maximum of $10,000 for failure to disclose a return. It can be imposed only by the IRS (and not by the person denied the return). The IRS can also impose a penalty on the person "responsible" for the failure, but such penalties seem highly unlikely if the failure was due to ignorance and disclosure was made immediately upon learning of the requirement.