File:Wikimedia DC Determination Letter.pdf

According to this official letter from the IRS:
 * Wikimedia DC is a a 501(c)(3) organization, as of 22 DEc 2014
 * Contributions to Wikimedia are deductible from U.S. federal taxes.
 * Wikimedia DC is a public charity, not a private foundation.
 * For more on compliance for such organizations, see IRS publication 4221-PC