Actually a sophisticated type of individual retirement account (IRA), the SIMPLE (Savings Incentive Match Plan for Employees) IRA plan allows employees to defer up to $13,000 for 2019 of annual compensation by contributing it to an IRA. In addition, employees age 50 and over may make an extra "catch-up" contribution of $3,000 for 2019. Employers are required to match deferrals, up to 3% of the contributing employee's wages (or make a fixed contribution of 2% to the accounts of all participating employees whether or not they defer to the SIMPLE plan).
SIMPLE plans work much like 401(k) plans, but do not have all the testing requirements. So, they're cheaper to maintain. There are several drawbacks, however. First, all contributions are immediately vested, meaning any money contributed by the employer immediately belongs to the employee (employer contributions are usually "earned" over a period of years in other retirement plans). Second, the amount of contributions the highly paid employees (usually the owners) can receive is severely limited compared to other plans. Finally, the employer cannot maintain any other retirement plans. SIMPLE plans cannot be utilized by employers with more than 100 employees.