Retirement — Private Sector
About this plan
A Single K plan is an individual 401(k) designed for owner-only businesses and the self-employed. With both salary deferral and profit sharing contributions, a Single K lets business owners maximize retirement savings up to the annual additions limit.
What's Included
For Employers
A Single K is one of the most powerful retirement savings tools for owner-only businesses. NBS handles the plan setup, annual compliance, and Form 5500 filing.
For Participants
Your Single K plan allows you to contribute as both employee and employer — maximizing your tax-advantaged retirement savings each year.
IRS Contribution Limits
Annual limits set by the IRS for tax-advantaged retirement contributions.
Elective Deferral Limit
All eligible employees
Age 50+ Catch-Up Contribution
Employees age 50 and older
Available if your plan permits.
Super Catch-Up Contribution
Employees ages 60–63 (SECURE 2.0)
Available if your plan permits.
Maximum Annual Additions
All contributions combined (employer + employee)
Age 50–59 & 64+
$32,500
Base $24,500 + catch-up $8,000
Ages 60–63 (SECURE 2.0)
$35,750
Base $24,500 + super catch-up $11,250
Combined totals assume your plan permits the applicable catch-up.
Catch-up contributions are plan-optional — your plan document governs which are available. Limits updated annually by the IRS. SECURE 2.0 super catch-up (ages 60–63) continues for 2026. View on IRS.gov →
NBS administers more than Single K Plans
Many employers use NBS across multiple benefit types — consolidating administration simplifies vendor management and gives your employees a consistent experience. You may also be interested in these related plans.
