what s the difference between a 401 a and 403 b 
a 401 a plan and a 403 b are both types of tax advantaged retirement plans available to certain public sector employees unlike a 401 a a 403 b plan is aimed at employees of public schools and tax exempt organizations and their investment options are limited to annuities or mutual funds the main difference is that an employer can make participation in a 401 a plan mandatory while it remains voluntary for employees to participate in a 403 b 