The SDRS Supplemental Retirement Plan is a voluntary 457(b) savings plan for employees of SDRS-participating employers. You can contribute pre-tax or Roth money, change your amount anytime, and use it to fill the gap your SDRS pension and Social Security leave. Employers can also auto-enrol new hires at $25 a month.
The SRP gives public employees another way to build retirement savings alongside their SDRS pension. Understanding contribution limits, tax options, catch-up contributions, and withdrawal choices can help you make better decisions throughout your career. This guide explains how the plan works and what to consider before contributing or withdrawing money.
WHY THE SRP EXISTS: THE INCOME GAP
SDRS is a 401(a) defined benefit pension. According to the SDRS Supplemental Retirement Plan brochure, the pension replaces about 50% of pay for a career member with 30 years of service. SDRS recommends at least 85% income replacement from all sources.
That leaves a gap. Social Security covers part of it, and personal savings must cover the rest. The SRP is the plan SDRS points members to for that third source.
SRP, SPP AND SPB: THREE ACRONYMS DECODED
South Dakota retirement materials use three similar names. They do different jobs.
| NAME | WHAT IT IS | WHO FUNDS IT |
|---|---|---|
| SRP (Supplemental Retirement Plan) | A 457(b) savings plan with pre-tax and Roth options | You, through payroll |
| SPP (Special Pay Plan) | A 401(a) plan for special pay, such as termination pay or retirement incentives | Your employer |
| SPB (Supplemental Pension Benefit) | An option to turn SRP or SPP money into extra lifetime monthly income through SDRS | Your existing SRP or SPP balance |
These plans serve different roles in retirement planning. The SRP is designed for ongoing employee savings, while the SPP applies to eligible employer-provided special pay. The SPB has a different purpose: it can provide additional lifetime monthly income by using eligible SRP or SPP savings. Knowing how each option works can help you understand your contribution limits, eligibility and retirement income choices.
SPP contributions don't reduce your SRP contribution limit, and SPP participants are fully vested right away. The SPB is available only to retirees who are already receiving an SDRS benefit.
FROM FIRST DAY TO LAST DAY: A TIMELINE
PRE-TAX OR ROTH IN THE SRP?
Pre-tax contributions lower your taxable pay now and are taxed when you withdraw them. Roth contributions are taxed now, and qualified withdrawals come out tax-free. The SRP offers both, so you can split contributions between them.
Which is better depends on your tax bracket now and later. Read when roth conversion worth tax bill to learn how to think about that trade-off.
RETIREMENT PLANS IN SIOUX FALLS: WHAT LOCAL EMPLOYEES SHOULD KNOW
Many Sioux Falls workers are covered by SDRS. The Sioux Falls School District lists SDRS as its retirement benefit and points staff to supplemental retirement benefits. Local news reports say the city's older pension plans closed to new members, and newer city hires, including police and firefighters, are in SDRS. Confirm your own status with HR.
South Dakota has no state income tax on individuals, according to the SDSU government information guide. Federal income tax still applies to SRP withdrawals, so your plan should focus on federal brackets and timing.
CHOOSING OUTSIDE HELP IN SIOUX FALLS
You can use the free planning tools that SDRS and the SRP offer. If you'd like a second opinion, look for someone who understands public-sector plans, including 457(b) rollovers and the SPB. Check registration on the SEC's adviser database, and ask how they are paid.
COMMON SRP MISTAKES TO AVOID
MISTAKES THAT COST YOU IN THE LONG RUN
- Staying at the $25 default for years without raising it
- Leaving your target-date fund untouched without ever reviewing it
- Rolling to an IRA before understanding the penalty rules
- Ignoring how a market drop just before retirement can affect your timing — see the market drop before retirement guide
- Skipping the conversation with a spouse — start with a family conversation before retirement
CONCLUSION
The SDRS Supplemental Retirement Plan is the main tool for closing the gap between your pension and the income you'll want. It's flexible, voluntary, and open to employees of SDRS-participating employers, including many in Sioux Falls. Consistent contributions over time can build a stronger financial cushion and give you more flexibility in retirement.
Start by checking your current contribution, then raise it when you can. Review it each year, and know your withdrawal options before you leave. Regular reviews can help ensure your savings strategy continues to match your retirement goals and changing financial needs.