A public hospital as defined in N.C. Gen. Stat. § 159-39(a) may acquire an ownership interest, in whole or in part, in a nonprofit or for-profit managed care company, including a health maintenance organization, physician hospital organization, physician organization, management services organization, or preferred provider organization with which the public hospital is also directly or indirectly a contracting provider. Ownership interest may be evidenced by the ownership or acquired by the purchase of stock. This ownership or acquisition of stock is the exercise of a health care function and is not the investment of idle funds within the meaning of N.C. Gen. Stat. § 159-30 and G.S.159-39(g). (1995 (Reg. Sess., 1996), c. 713, s. 1.)