Retirement plan sponsors are companies or employers who set up a retirement plan for employees, according to Investopedia. Retirement sponsors determine an employee's contribution payment and where to invest the money. They may also provide contribution payment in the form of cash or stock.
Employers offer a 401(k) or 403(b) retirement plan that withholds employees contribution through a payroll deduction, according to U.S. News & World Report. As of 2015, employees save up to $18,000 of pretax income or $24,000 for those aged 50 or older. For-profit companies offer 401(k) retirement plans, and nonprofit organizations offer 403(b) retirement plans. Other retirement plans include Solo 401(k) for sole proprietors, Simplified Employee Pension, Simple IRA, IRA and Roth IRA.