Breaking Down the TSP Investment Funds (2024)

The Thrift Savings Plan (TSP)offered to all U.S. government employeesis 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 availableorare 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.


The five core funds offered in the Thrift Savings Planloosely cover the basic range of publicly traded debt and equity securities. All five funds are managed by BlackrockCapital Advisers and State Street Global Advisors and are available only toTSPparticipants. None of them trade on any public exchange, althoughBlackrockdoes offer publicly traded equivalents of some TSPfunds throughiShares, its subsidiary company, which offers a comprehensive range ofETFs.

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 fundscommingled 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 TSPfund's share priceis 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 specialnon-marketabletreasury security issued specifically for theTSPby the U.S. government. This fund is the only one in theTSPthat 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 theTSP by new plan participantswas 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 4 years or more.

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 theTSP. This index invests in a wide range of debt instruments, including publicly traded treasury and government agency securities, corporate and non-corporate bonds,and asset-backed securities (ABS).

This fund also pays monthly interest typically exceedingthat paid by the G Fund. However, it does not guarantee the return of the investor’s principal. The BlackRock iSharesequivalentETFis theiSharesCore U.S. Aggregate Bond Market ETF (AGG).

Common Stock Index Investment Fund (C Fund)

This fund is the most conservative of the three stock funds available in theTSP. 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 Fundsand has posted commensurately higher returns over time. The BlackRock iSharesequivalentETFis theiSharesCore S&P 500 (IVV).

Small-Capitalization Stock Index Fund (S Fund)

The S Fund holds the samesecurities asthe Dow Jones U.S. Completion Total Stock Market Index. This index is composed of over 4,000 companies and "designed to measure all U.S. equities with readily available prices."

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 theTSP. It has outperformed the C Fund with proportionately greater volatility over time.

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

  • iShares Russell Midcap ETF (IWR)
  • iShares Russell 2000 Index ETF (small caps only) (IWM)
  • iShares Core S&P Total U.S. Stock Market ETF (ITOT)
  • iShares Russell 3000 ETF (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 investingin larger, more established companies located in 21 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 TSPthat investsin companies outside the U.S. The BlackRock iShares equivalent ETF is the iShares MSCI EAFE ETF (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 thefive core funds and act liketarget-date fundsby nature. They 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 governmentservice.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 ThriftSavings 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.

Breaking Down the TSP Investment Funds (2024)


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