Generally, you will be informed of your eligibility to participate in the Optional Retirement Program (ORP) at the time of your initial employment. Eligibility is strictly determined by the job you perform and is not based on years of service or salary level. To be eligible to participate in ORP, an employee must: (1) initially be appointed on a full-time basis for four and one-half months or more; and (2) be appointed to a position otherwise eligible to participate in ORP. Employees who are eligible to participate in a Retirement Program who are not eligible to participate in ORP must participate in the Teacher Retirement System of Texas (TRS).