Breaking Down the TSP Investment Funds

The Thrift Savings Plan (TSP) offered to all U.S. government employees is one of the simplest and most efficient retirement plans in use today. But while thousands of civilian and military employees defer a portion of their earnings into the plan each year, many participants do not understand the actual fund options available or are unsure which funds are appropriate for them.

This article breaks down the five core investment funds available in the TSP along with the Lifecycle funds and their proper use.

Key Takeaways

  • Thrift Savings Plans (TSPs) are direct-contribution retirement plans offered to U.S. government employees.
  • Similar to the 401(k) plans offered by private-sector employers, TSPs offer five core mutual funds to invest in, four of which are diversified index funds.
  • Each index fund specializes in a different asset class or market segment, such as U.S. equities, international equities, and corporate bonds.
  • The fifth core fund, the G Fund, invests in very low-risk, low-yield government bonds and guarantees principal protection to investors. The G Fund is intended for very conservative investors.
  • A Lifecycle (L) Fund serves as the default fund for new plan participants who don't specify a contribution allocation when they make their contribution.

Click Play to Learn About Thrift Savings Plans

Core TSP Funds

The five core funds offered in the Thrift Savings Plan loosely cover the basic range of publicly traded debt and equity securities. All five funds are managed by Blackrock Capital Advisers and are available only to TSP participants. None of them trade on any public exchange, although Blackrock does offer publicly traded equivalents of some TSP funds through iShares, its subsidiary company, which offers a comprehensive range of ETFs.

Four of the five funds are index funds, which hold securities exactly matching a broad market index. The money participants place in the F and C Funds is invested in separate accounts, while the S and I Fund monies are invested in trust funds commingled with other tax-exempt pension and endowment funds.

All of the funds, except for the G Fund, are 100% invested in their respective indexes, and they do not take into account the current or overall performance of either the specific index or the economy as a whole. Each TSP fund's share price is calculated daily and reflects investment returns minus administrative and trading costs. The five funds are broken down below.

Government Securities Investment Fund (G Fund)

This is the only core fund that does not invest in an index. The G Fund invests in a special non-marketable treasury security issued specifically for the TSP by the U.S. government. This fund is the only one in the TSP that guarantees the return of the investor’s principal.

This fund thus has the lowest risk of the five funds, and, until Sept. 15, 2015, money contributed into the TSP by new plan participants was placed into this fund by default unless the participant specified otherwise (as of that date, the default investment fund changed to the Lifecycle (L) Fund most appropriate for the participant's age). It pays an interest rate based on nonmarketable short-term treasury securities with a maturity of a few days to 52 weeks.

The G Fund has historically provided the lowest rate of return of any of the core funds.

Fixed-Income Investment Index Fund (F Fund)

This fund represents the next step up the risk/reward ladder in the TSP. This index invests in a wide range of debt instruments, including publicly traded treasury and government agency securities, corporate and foreign bonds, and mortgage-backed securities (MBS).

This fund also pays monthly interest typically exceeding that paid by the G Fund. However, it does not guarantee the return of the investor’s principal. The Barclays iShares equivalent ETF is the iShares Core Total U.S. Bond Market ETF (ARCA:AGG).

Common Stock Index Investment Fund (C Fund)

This fund is the most conservative of the three stock funds available in the TSP. The C Fund invests in the 500 large and mid-cap companies that comprise the Standard and Poor’s 500 Index. This fund has experienced greater volatility than either the G or F Funds and has posted commensurately higher returns over time. The Barclays iShares equivalent ETF is the iShares Core S&P 500 (ARCA:IVV).

Small-Capitalization Stock Index Fund (S Fund)

The S Fund holds the same securities as the Dow Jones U.S. Completion Total Stock Market Index. This index is composed of the 4,500 companies outside of the Standard & Poor’s 500 Index that make up the rest of the Wilshire 5000 Index, the broadest of the stock indexes.

As the fund name indicates, these companies are smaller and less established than the S&P 500 companies and have greater potential for growth than those in the C Fund. The S Fund is considered one of two funds with the greatest risk in the TSP. It has outperformed the C Fund with proportionately greater volatility over time.

The Barclays iShares has no exact S Fund equivalents. Those who wish to duplicate this fund outside the TSP could use the following four funds to cover many of the companies in the S Fund (and some that are not):

  • Russell Midcap ETF (ARCA:IWR)
  • Russell 2000 Index ETF (small caps only) (ARCA:IWM)
  • iShares Core S&P Total U.S. Stock Market ETF (ARCA:ITOT)
  • Russell 3000 ETF (ARCA:IWV)

International Stock Index Investment Fund (I Fund)

This fund invests in securities mirroring the Morgan Stanley Capital International EAFE (Europe, Australasia, Far East) Index. This is one of the broader international indexes investing in larger, more established companies located in 22 developed countries around the world. It is regarded as the other high-risk fund in the TSP and has historically posted a higher average annual return than the C Fund.

This fund is the only one in the TSP that invests in companies outside the U.S. The Barclays iShares equivalent ETF is the iShares MSCI Europe, Australasia and Far East ETF (ticker symbol EFA).

New plan participants who don't feel qualified or neglect to designate an asset allocation for their contributions can feel confident that the default Lifecycle (L) Fund that they're assigned will invest their money in an allocation that's appropriate for their age and years until retirement.

Lifecycle Funds (L Funds)

The Lifecycle funds are composite funds that invest in a combination of the five core funds and act like target-date funds by nature. They are designed and managed by the portfolio managers at Blackrock Capital and function as "automatic pilot" funds for participants who do not wish to make their own asset allocations. They invest primarily in the stock funds when they are issued and are then slowly reallocated by the fund managers into the two bond funds every 90 days until they mature.

The L Income fund's asset allocations include 77% invested in the bond funds, and the remaining 23% divided between the three stock funds.

Participants should take care to match the maturity date of the L Fund they choose with the time they actually begin receiving distributions, instead of when they merely separate from government service. Each is designed to provide income for those who will begin taking distributions within five years of the maturity date.

They also offer the best possible mix of growth versus reward during both the growth and income phases of each fund. The L Income Fund can be used by those who have already retired and need a conservative stream of income at the present time.

Role as Default Fund

Since Sept. 15, 2015, an age-appropriate L Fund has been the default fund for new civilian TSP participants as well as the spouse beneficiaries of civilian participants who have passed away. An age-appropriate default L Fund is assigned unless the new participant/beneficiary specifies an allocation when they make their contribution to the plan. The retirement age of 63 is used to determine which L Fund is selected for a participant.

TSP Investment Programs

Although the L Funds provide one avenue of professional portfolio management for TSP participants, some privately managed TSP investment programs may provide additional clout for aggressive investors. offers several levels of market-timing strategies, and provides additional commentary and ideas. 

Those who seek higher returns and are willing to take on additional risk can search online for other proprietary market-timing strategies that may beat the indexes over time. Of course, many of these programs charge a quarterly or annual fee for their services, and they cannot guarantee their results.

The Bottom Line

The Thrift Savings Plan offers participants the options of growth, income, and capital preservation. The annual investment expenses in this plan are among the lowest in the industry, and all of the funds are fully transparent. There are no hidden fees in this plan, and participants should think carefully before rolling their plan assets elsewhere when they retire.

Article Sources
Investopedia requires writers to use primary sources to support their work. These include white papers, government data, original reporting, and interviews with industry experts. We also reference original research from other reputable publishers where appropriate. You can learn more about the standards we follow in producing accurate, unbiased content in our editorial policy.
  1. Thrift Savings Plan. "Fund Management," Download "Summary of the Thrift Savings Plan."

  2. Thrift Savings Plan. "Default Investment Fund for Civilian and Beneficiary TSP Participants."

  3. Thrift Savings Plan. "G Fund composition."

  4. Thrift Savings Plan. "G Fund: Government Securities Investment Fund."

  5. Thrift Savings Plan. "F Fund: Fixed Income Index Investment Fund."

  6. iShares. "iShares Core U.S. Aggregate Bond ETF."

  7. Thrift Savings Plan. "C Fund: Common Stock Index Investment Fund."

  8. iShares. "iShares Core S&P 500 ETF."

  9. S&P Dow Jones Indices. "Dow Jones U.S. Total Stock Market Index."

  10. Thrift Savings Plan. "S Fund: Small Cap Stock Index Investment Fund."

  11. iShares. "iShares Russell Mid-Cap ETF."

  12. iShares. "iShares Russell 2000 ETF."

  13. iShares. "iShares Core S&P Total U.S. Stock Market ETF."

  14. iShares. "iShares Russell 3000 ETF."

  15. MSCI. "MSCI EAFE Index (USD)."

  16. iShares. "iShares MSCI EAFE ETF."

  17. Thrift Savings Plan. "L Income."

  18. Thrift Savings Plan. "Lifecycle Funds," Download "L Funds Information Sheet."

Take the Next Step to Invest
The offers that appear in this table are from partnerships from which Investopedia receives compensation. This compensation may impact how and where listings appear. Investopedia does not include all offers available in the marketplace.
Take the Next Step to Invest
The offers that appear in this table are from partnerships from which Investopedia receives compensation. This compensation may impact how and where listings appear. Investopedia does not include all offers available in the marketplace.