Explore contribution limits and learn how much you can contribute to your plan. Tax-deferred annuity plans or TDAs are tax-deferred retirement plans available to employees of community colleges, state colleges, universities, and other qualified individuals employed in an educational capacity including the Board of Higher Education. As interest rates rise, bond prices usually fall, and vice versa. To Enroll Now: Obtain your 5 digit plan number, contact Fidelity at or your benefits office. Choose your Investments.