In technical terms, your ASRS pension plan is a 401(a) Defined Benefit plan, while a 401(k) is classified as a Defined Contribution plan. Your ASRS pension plan is a 401(a) Defined Benefit plan, while a 401(k) is classified as a Defined Contribution plan.You may use this form to request Arizona income tax be withheld if you receive a payment from a pension, annuity, or a distribution from a retirement account. Open an Account: Open your Individual 401(k) account with the chosen provider. Arizona Deferred Compensation - The State of Arizona offers retirement plans for state employees to put aside money from each paycheck toward retirement. Should you participate in a state-run IRA or offer your employees a 401(k) plan? Employees can participate in two different retirement plans - ASRS or ORP. They also have the option to enroll in supplemental retirement plans. If you need assistance establishing your business' retirement plan in AZ, the Mesa small business lawyers at JacksonWhite can walk you through the process. You must report information on the retirement plan each year.