TSP vs. Fidelity and Vanguard: A $1 Million Retirement Case Study

For some federal employees approaching retirement, a natural question emerges: should you leave your money in the Thrift Savings Plan or move it to an IRA at Fidelity Investments or Vanguard?

You can buy low-cost index funds that mirror the TSP and, in some cases, reduce expenses slightly. But when you examine the numbers and the trade-offs more closely, the decision becomes less about cost and more about control, risk, and income design.

Let’s walk through a realistic case.

The Portfolio and the Withdrawal Scenario

A retired federal employee rolls over a $1,000,000 TSP balance at age 65. The portfolio is allocated similarly in both cases:

• 40% large U.S. stocks (C Fund equivalent)
• 20% small/mid U.S. stocks (S Fund equivalent)
• 20% international stocks (I Fund equivalent)
• 20% bonds

In the TSP, that bond allocation is split between the F Fund and the uniquely structured G Fund. In the IRA, it is replaced with a total bond market index fund.

The retiree withdraws $40,000 per year, to be adjusted for inflation.

The Cost Comparison

The TSP’s expense ratio averages around 0.05%. Comparable index funds at Fidelity or Vanguard may come in slightly lower, closer to 0.03%. On a $1 million portfolio, that difference amounts to roughly $200 per year. Over a 20-year retirement, assuming stable balances, the total savings might reach $4,000 to $6,000.

That is real money, but in the context of a $1 million portfolio generating decades of income, it is not a decisive factor. Investment returns, withdrawal strategy, and tax management will have far greater financial impact.

Portfolio Behavior: The Hidden Difference

The more meaningful distinction emerges during market stress.

In the TSP, the G Fund provides something no private-sector investment can replicate. It offers government-backed principal stability with yields typically higher than short-term Treasury funds. During market downturns, it acts as a shock absorber without exposing the retiree to interest rate volatility.

In the IRA versions of this portfolio, the bond allocation replaces the G Fund with a total bond market fund. While diversified, it can decline in value when interest rates rise or markets reprice risk.

In a year like 2022, for example, both stocks and bonds declined. A TSP investor with a meaningful G Fund allocation experienced less volatility than an IRA investor relying entirely on market-based bonds.

That difference becomes critical when withdrawals are occurring. Losses combined with withdrawals can permanently reduce portfolio longevity, a phenomenon often referred to as sequence risk.

Withdrawal Flexibility

Where the IRA clearly pulls ahead is flexibility.

At Fidelity or Vanguard, the retiree can precisely control which assets are sold, coordinate withdrawals with tax brackets, and implement strategies such as Roth conversions to manage future Required Minimum Distributions and Medicare IRMAA thresholds.

The TSP has improved its withdrawal options in recent years, but it still does not offer the same level of granular control. For retirees who intend to actively manage taxes and income streams, this flexibility can create meaningful long-term value.

A Side-by-Side Outcome

After 20 years, assuming similar market returns, both portfolios are likely to end in a comparable range. The IRA may show a slight advantage from marginally lower fees and tax optimization strategies, while the TSP may demonstrate greater stability due to the G Fund’s role in dampening volatility.

The difference in outcomes is not driven by expense ratios. It is driven by behavior during difficult markets and the retiree’s ability to manage withdrawals intelligently.

What This Means for Federal Retirees

For federal retirees, this is not simply an investment decision. It is a retirement income decision.

If your priority is simplicity, stability, and a built-in risk buffer, the TSP remains one of the most efficient retirement systems available. The presence of the G Fund alone makes it structurally different from any IRA.

If your priority is control, tax planning, and customization, an IRA at Fidelity or Vanguard provides tools the TSP cannot match.

Many retirees ultimately choose a hybrid approach, keeping a portion of assets in the TSP to preserve access to the G Fund while rolling over the rest to an IRA for flexibility.

The Bottom Line

It is entirely possible to replicate the TSP using low-cost index funds at Fidelity or Vanguard, and you may save a small amount in fees.

But the real decision is not about shaving a few basis points. It is about choosing between a system designed for simplicity and stability, and one designed for flexibility and control.

For most federal retirees, that distinction will matter far more than the difference between 0.05% and 0.03%.