A cash balance plan’s annual interest credit is capped by what Treasury regulations call a market rate of return, and for a cash balance plan that ceiling limits the rate to one of a defined list: a fixed rate up to 6%, a Treasury yield with a capped margin, a corporate bond segment rate, an eligible cost-of-living index, or the actual return on the plan’s diversified investments. Pick something outside that list, or stack a margin on top that the regulation doesn’t allow, and the plan risks losing its tax-qualified status.
Where the Ceiling Comes From
The rule sits at 26 CFR 1.411(b)(5)-1(d). It tells cash balance sponsors that whatever rate the plan document uses to credit interest on hypothetical account balances, that rate cannot exceed a market rate of return.1eCFR. 26 CFR 1.411(b)(5)-1 – Reduction in Rate of Benefit Accrual Under a Defined Benefit Plan In practice, the regulation does the defining for you: it lists the acceptable rates, and anything outside the list is presumptively too high.
That is why a plan cannot credit, say, an S&P 500 index return with a 2% add-on. The design would exceed a market rate and violate the rules. The framework is meant to keep tax-advantaged pension dollars from being used to promise returns Congress did not authorize.
The Safe Harbor Rates You Can Use
Paragraph (d)(4) of the regulation lists the rates a plan can use without any further showing. Choose one of these and the market rate ceiling is automatically satisfied.
Treasury Yields With Capped Margins
The regulation lets a plan tie its credit to a Treasury security, but the margin you can add shrinks as the maturity lengthens:
- 3-month Treasury bill discount rate: up to 175 basis points
- 12-month or shorter Treasury bill discount rate: up to 150 basis points
- 1-year Treasury constant maturity yield: up to 100 basis points
- 3-year or shorter Treasury constant maturity yield: up to 50 basis points
- 7-year or shorter Treasury constant maturity yield: up to 25 basis points
- 30-year or shorter Treasury constant maturity yield: no margin
The 30-year Treasury is a common choice precisely because no margin is allowed. It functions as a straight pass-through of long-term government debt performance.
Corporate Bond Segment Rates
A plan can also use the first, second, or third segment rate described in IRC 430(h)(2)(C). These reflect yields on investment-grade corporate bonds across short, mid, and long maturities. The third segment rate may include a guaranteed annual floor of up to 4%.2Internal Revenue Service. Issue Snapshot – How to Change Interest Crediting Rates in a Cash Balance Plan Segment rates generally run slightly higher than Treasuries because they carry corporate credit risk.
Cost-of-Living Indices
An eligible cost-of-living index, including the Consumer Price Index, can serve as the crediting rate. For certain indices, the regulation permits a margin of up to 300 basis points above the index.1eCFR. 26 CFR 1.411(b)(5)-1 – Reduction in Rate of Benefit Accrual Under a Defined Benefit Plan
A Flat Rate Up to 6%
A fixed annual crediting rate of up to 6% qualifies on its own.1eCFR. 26 CFR 1.411(b)(5)-1 – Reduction in Rate of Benefit Accrual Under a Defined Benefit Plan It is administratively simple and gives the sponsor a predictable cost. Participants receive the same credit in every market.
Floors and Caps
Plans often pair a variable rate with a minimum floor, so a participant receives the higher of the benchmark or the guarantee. Floors are allowed, but the regulation limits how generous the guarantee can be relative to the underlying rate. For the third segment rate, the maximum guarantee is 4% applied annually or cumulatively.2Internal Revenue Service. Issue Snapshot – How to Change Interest Crediting Rates in a Cash Balance Plan Setting a cap so low that the rate no longer behaves like a real market return can push the plan out of compliance from the other direction.
Using the Plan’s Actual Investment Return
Some plans skip external benchmarks and credit interest equal to the net return on the trust’s own investments. This aligns account growth with the plan’s real funding experience and removes the mismatch between a benchmark and the actual portfolio.
To use actual returns, the trust has to be diversified. It needs a broad mix of equities, bonds, and other conventional assets, managed without large concentrated bets. A portfolio loaded with illiquid private equity or hard-to-value real estate would not qualify. The credit is calculated from the return after investment expenses and management fees.1eCFR. 26 CFR 1.411(b)(5)-1 – Reduction in Rate of Benefit Accrual Under a Defined Benefit Plan
The upside is higher credits in strong years. The downside is that credits can go negative in down years, which is where the next rule steps in.
The Preservation of Capital Floor
Whatever crediting method the plan uses, the participant has a cumulative safety net at the finish line. Under 26 CFR 1.411(b)(5)-1(d)(2), the benefit payable at the annuity starting date cannot be less than the sum of all principal credits the employer has posted to that participant’s hypothetical account, reduced only for prior distributions.1eCFR. 26 CFR 1.411(b)(5)-1 – Reduction in Rate of Benefit Accrual Under a Defined Benefit Plan
If negative interest credits over the years have dragged the hypothetical balance below the total of employer principal credits, the sponsor makes up the shortfall when the participant begins receiving distributions.3Internal Revenue Service. Cash Balance Plan Legal Reference Material In a 401(k), your balance can drop to whatever the market dictates. In a cash balance plan, you will not walk away with less than the total principal credits. The employer absorbs the tail risk, which is one reason some sponsors prefer fixed or Treasury-based crediting rates that make a shortfall unlikely in the first place.
Changing the Rate After the Plan Is in Place
Switching a plan from one interest crediting rate to another is not a simple amendment. The anti-cutback rule under IRC 411(d)(6) treats the right to future interest credits on an already-accrued balance as a protected benefit. If the new rate could produce a smaller credit than the old rate on that existing balance, the plan has to preserve the old rate for the portion already earned.2Internal Revenue Service. Issue Snapshot – How to Change Interest Crediting Rates in a Cash Balance Plan
Two methods are standard. Under the A-plus-B approach, the plan keeps two hypothetical accounts. The A account holds the balance frozen at the change date and continues earning the old rate; no new principal credits go in. The B account starts at zero and receives all future principal credits at the new rate. The participant’s total benefit is A plus B.
Under the wearaway method, the participant’s benefit is the greater of two figures: the change-date balance grown forward at the old rate, or the change-date balance plus new principal credits grown forward at the new rate. Over time the new-rate figure typically overtakes the old-rate figure and the old calculation drops out. Wearaway is available for active participants still earning principal credits. For terminated participants, it can be used only if the combination of the old and new rates independently satisfies the market rate of return rules; otherwise the plan has to use A-plus-B or another compliant structure for that group.
The 204(h) Notice
When the amendment significantly reduces future accruals, participants must receive a Section 204(h) notice before it takes effect. Large plans (100 or more participants with accrued benefits) need to give at least 45 days’ notice. Small plans and multiemployer plans need at least 15 days, as do amendments tied to a business acquisition or disposition.4eCFR. 26 CFR 54.4980F-1 – Notice Requirements for Certain Pension Plan Amendments Significantly Reducing the Rate of Future Benefit Accrual The notice has to describe the pre-amendment formula, the post-amendment formula, and the effective date, with enough additional explanation or examples that a participant can gauge the practical impact.
What Non-Compliance Costs
Missing a 204(h) deadline triggers an excise tax under IRC 4980F of $100 per day per affected participant.5Internal Revenue Service. Chapter 11 Cash Balance Plans For unintentional failures where the sponsor exercised reasonable diligence, the total is capped at $500,000. If the sponsor corrects within 30 days of discovery, or can show the failure was not discovered despite reasonable due diligence, no tax applies.
The bigger exposure is on the substantive rate itself. If the IRS finds that a plan’s interest crediting rate exceeds the market rate ceiling, the plan can lose its tax-qualified status. Capping a stated rate below what the document promises has separately been treated as an impermissible forfeiture under IRC 411(a). Drafting the crediting rate correctly at the outset is far cheaper than fixing it after the fact.