The Pre-election Presidential Transition Act of 2010 is headed to the President’s desk.
An “eligible candidate” (a term defined in the law) is authorized to create a 501(c)(4), as this section explains:
Notwithstanding any other provision of law, an eligible candidate may establish a separate fund for the payment of expenditures in connection with the eligible candidate’s preparations for the assumption of official duties as President or Vice-President, including expenditures in connection with any services or facilities provided under this subsection (whether before such services or facilities are available under this section or to supplement such services or facilities when so provided). Such fund shall be established and maintained in such manner as to qualify such fund for purposes of section 501(c)(4) of the Internal Revenue Code of 1986.
The Obama-Biden Transition Project was a 501(c)(4).