N.J. Stat. Ann. § 43:10-111

The governing body of such county shall have the management and control of said fund and is hereby empowered to make all necessary rules and regulations concerning the same not inconsistent with this act; all moneys not needed for the immediate payment of pensions shall be invested by the governing body in interest-bearing bonds of any county of this State, or in any other interest-bearing securities in which savings banks of this State are authorized to invest their funds.