The main purpose of this legislation is to improve 403(b) retirement plans, which are primarily used by employees of public schools and certain non-profit organizations. The goal is to make these plans more accessible and beneficial for employees, ensuring they have better options for saving for retirement. Key provisions of the legislation include changes to existing laws that govern investment companies and securities. It updates definitions and requirements related to 403(b) plans, allowing them to be treated similarly to other retirement plans under federal securities laws.