501.
Exemption from tax on corporations, certain trusts, etc.
502.
Feeder organizations.
503.
Requirements for exemption.
504.
Status after organization ceases to qualify for exemption under section 501(c)(3) because of substantial lobbying or because of political activities.
505.
Additional requirements for organizations described in paragraph (9) or (17) of section 501(c).
506.
Organizations required to notify Secretary of intent to operate under 501(c)(4).