Final answer:
The ERISA minimum eligibility requirement for 401(k) plans is being 21 years old and having at least one year of service.
Step-by-step explanation:
The general minimum eligibility requirement set by ERISA for employer-sponsored 401(k) plans is that employees must be at least 21 years of age and have at least 12 months of service with the employer. These defined contribution plans, such as 401(k)s and 403(b)s, allow employers to contribute a fixed amount to the worker's retirement account on a regular basis, usually with every paycheck. The employee often contributes as well, and these contributions are invested in a variety of investment vehicles. These retirement plans are not only tax-deferred but also portable, which gives employees the flexibility to take their 401(k) plans with them if they change jobs.