What Federal Employees With a FERS Pension Are Getting Wrong About Their TSP

A federal employee with 30 years of service and a $90,000 high-3 average salary receives only $27,000 annually under FERS, just 30% of pre-retirement income. To bridge that gap, employees must navigate 2026 rules including the mandatory Roth catch-up for high earners and the persistent COLA gap between FERS and Social Security.

The Pension Math Most Federal Workers Get Wrong

The FERS basic annuity formula pays 1% of your high-3 average salary for each year of service, or 1.1% for those who retire at 62 or older with at least 20 years. A federal employee with 30 years of service and a $90,000 high-3 average salary receives a pension of roughly $27,000 per year before taxes. That works out to 30% of pre-retirement income, well short of the 60% to 70% replacement rate many workers expect going in.

The 2026 calculation still uses the High-3 average salary. While H.R. 1, passed by the House in 2025, included a provision to shift new retirees to a High-5 calculation beginning January 2028, that legislation has not yet been enacted into law. What makes relying on the pension alone increasingly dangerous, however, is the FERS COLA gap. In 2026, Social Security and CSRS beneficiaries received a 2.8% cost-of-living adjustment; FERS retirees were capped at 2.0% because of a statutory formula that limits FERS COLAs whenever inflation runs between 2% and 3%. That recurring shortfall compounds over time and makes strong TSP growth a necessity rather than an option.

Social Security serves as the second leg of the FERS three-legged stool. Employees who retire before age 62 may qualify for the FERS Special Retirement Supplement, which bridges the gap until Social Security benefits begin. That supplement is now directly in the legislative crosshairs: H.R. 1 as passed by the House includes a provision to eliminate the supplement beginning January 2028 for retirees not yet entitled to it at enactment, though the bill has not become law. Employees planning an early retirement should model their income projections both with and without the supplement, given its uncertain status.

The Default Fund Is Costing Years of Growth

The TSP no longer uses the G Fund as the default investment for most participants. Since 2015 for civilian employees, new enrollees are automatically placed in an age-appropriate Lifecycle (L) Fund. These target-date funds hold a diversified mix of stocks, bonds, and government securities, shifting gradually toward more conservative allocations as the target retirement date approaches. The TSP launched a new L 2075 Fund in 2025 for participants with roughly 50 years until retirement, and the plan’s total assets crossed $1 trillion during 2025 while serving more than 7.2 million accounts.

That said, the G Fund remains the most conservative option available in the TSP. It earned approximately 4.4% in 2025 and carries essentially no market risk, but its long-term growth potential is limited relative to current inflation levels.

The C Fund, which tracks the S&P 500, has averaged approximately 10% to 12% annually since the fund launched in 1988, depending on the measurement period. For a FERS retiree whose pension COLA is already capped by statute, the difference between G Fund stability and C Fund growth often determines whether purchasing power is maintained or steadily eroded throughout retirement.

The Super Catch-Up and the “Mandatory Roth” Trap

For federal employees between 60 and 63, SECURE 2.0 created a significant contribution window. The standard 2026 TSP elective deferral limit is $24,500. Employees who turn 60, 61, 62, or 63 during the 2026 calendar year qualify for a “Super Catch-Up” limit of $11,250, bringing the total allowable deferral to $35,750. Once an employee turns 64, the catch-up limit reverts to the standard $8,000, making this window time-sensitive.

Crucial for 2026: Under SECURE 2.0 implementation rules now in effect, if your 2025 wages exceeded $150,000, your catch-up contributions must be designated as Roth TSP contributions. The spillover system handles this automatically once regular contributions reach the $24,500 ceiling, but the practical result is the same: those extra dollars go in after-tax rather than pre-tax. Senior GS-14 and GS-15 employees, particularly those in high-locality pay areas, need to budget for the reduction in monthly take-home pay that accompanies this shift.

A related development took effect in January 2026: the TSP began allowing in-plan Roth conversions, giving participants the ability to transfer existing traditional (pre-tax) balances into Roth status within the same account. Converting creates a taxable event in the year of the conversion, but it removes those funds from future required minimum distribution requirements and positions withdrawals to be tax-free. For federal employees who expect to be in a higher bracket during retirement than they are today, a ladder of smaller conversions over several years can spread the tax cost.

The IRA Deductibility Rule Federal Employees Misread

Because federal employees are covered by a workplace retirement plan (the TSP), many assume they cannot deduct a traditional IRA contribution. That assumption is often wrong when applied to the household as a whole.

In 2026, a spouse who does not participate in a workplace retirement plan can deduct a full traditional IRA contribution if household MAGI is below $242,000, with the deduction phasing out entirely at $252,000. The IRA contribution limit for those 50 and older is $8,600 in 2026. This creates a second tax-advantaged savings bucket for high-earning federal households, even when the federal employee has exceeded their own personal deduction threshold.

The employees themselves face a tighter phase-out window. For 2026, married filers who are covered by a workplace retirement plan see their own IRA deduction phase out between $129,000 and $149,000. Many mid-career GS employees fall within this range and may still qualify for at least a partial deduction on their own contribution.

Contribution and Allocation Steps for the 2026 Plan Year

1. Audit Your Risk: With FERS COLAs capped well below CSRS and Social Security, review any heavy G Fund allocation. Employees more than five years from retirement who hold most of their TSP in the G Fund face meaningful purchasing power erosion over time, because even a modest inflation gap compounds into a significant real-dollar shortfall across a 20-year or 30-year retirement.
2. Maximize the Window: If you are in the age 60-63 bracket, adjust your payroll contributions to reach the $35,750 ceiling. High earners above the $150,000 prior-year wage threshold should confirm that their agency payroll system is routing catch-up contributions to the Roth TSP side, as required under the 2026 mandatory Roth provision.
3. Spousal Coordination: Compare your 2026 MAGI against the new $242,000 threshold for a non-covered spouse. A deductible traditional IRA contribution for a spouse not covered by any workplace plan is one of the most consistently overlooked ways for federal households to reduce their current-year tax bill, and the 2026 limit of $8,600 (for those 50 and older) makes it meaningfully larger than it was just a few years ago.

Editor’s note: This article was updated to correct the 2026 traditional IRA deductibility phase-out range for married federal employees covered by a workplace plan (now $129,000 to $149,000, not the previously stated $123,000 to $143,000), to reflect the confirmed mandatory Roth catch-up income threshold of $150,000 in prior-year wages, and to add context on H.R. 1’s proposed elimination of the FERS annuity supplement beginning January 2028 and the TSP’s new in-plan Roth conversion feature launched in January 2026.

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