Participation is available to employees working in covered employment, which is employment in a job classification covered by a local collective bargaining agreement, which requires contribution to the IPF. Corporate officers who are employees of the corporation may also participate subject to the approval of the Trustees. Participation is also available to officers or employees of local unions or local union funds which participate in the IPF. Participation is not available to anyone engaged as a self-employed person, partner or sole proprietor.