(1) The Wisconsin retirement system is established as a governmental plan and as a qualified plan for federal income tax purposes under the 240.015 PUBLIC EMPLOYEE TRUST FUND Internal Revenue Code and shall be so maintained and administered.
(2) No benefit plan authorized under this chapter may be administered in a manner which violates an Internal Revenue Code provision that authorizes or regulates that benefit plan or which would cause an otherwise tax exempt benefit to become taxable under the Internal Revenue Code.
(3) For the purposes of compliance with the Internal Revenue Code, the plan year is January 1 through December 31.