Thowback Thursday Classic Post – TSP Fund Deep Dive – The F Fund

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There are only five investments available in the Thrift Savings Plan (TSP), so let’s take a detailed look at them one at a time. In this post we’ll cover the F Fund.

Inception Date

29 JAN 1988

Fund Management

The Federal Retirement Thrift Investment Board currently contracts BlackRock Institutional Trust Company, N.A. (BlackRock) to manage the F Fund assets. The F Fund remains invested regardless of the performance of the securities markets or the overall economy.

Investment Strategy

The F Fund is invested in a bond index fund that invests in government, corporate, and mortgage-backed bonds. The F Fund’s objective is to match the performance of the Bloomberg Barclays U.S. Aggregate Bond Index.

The F Fund is a passively managed fund that remains invested according to its indexed investment strategy regardless of securities market movements or general economic conditions.

What is the Risk?

Your investment in the F Fund is subject to market risk, credit risk, prepayment risk, and inflation risk.

Because the F Fund returns move up and down with the returns in the bond market, your F Fund investment is subject to market risk. For example, when interest rates rise, bond prices (and thus, the returns of the index and the F Fund) fall. Conversely, in an environment of falling interest rates, bond prices, as well as the index and F Fund returns, rise.

As an F Fund investor, you are also exposed to credit (default) risk, or the possibility that principal and interest payments on the bonds that comprise the index will not be paid.

The F Fund is subject to inflation risk, meaning your F Fund investment may not grow enough to offset the reduction in purchasing power that results from inflation.

Your F Fund investment is also exposed to prepayment risk, which is the probability that if interest rates fall, bonds that are represented in the index will be paid back early thus forcing lenders to reinvest at lower rates.

What is the Benefit?

Although there are several types of risks associated with the F Fund, the overall risk is relatively low in comparison to certain other fixed income investments in the market because the F Fund includes only investment-grade securities. As a result, F Fund investors are rewarded with the opportunity to earn higher rates of return over the long term than they would from investments in short-term securities such as the G Fund. Here is all the performance data as of 14 NOV 2020:

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Types of Earnings

The F Fund changes in value as the market price of its bond holdings change. In addition, the F Fund makes money for its investors with capital gains (net of trading costs), interest on notes and bonds, interest on short-term investments, and securities lending income.

BlackRock credits interest income each business day. This income is then reflected in the TSP share prices.

Share Price Calculations

The value of your account is determined each business day based on the daily share price and the number of shares you hold. At the end of each business day, after the stock and bond markets have closed, the total value of the funds’ holdings (net of accrued administrative expenses) is divided by the total number of shares outstanding to determine the share price for that day. The daily change in TSP share prices reflects all investment income (interest on short-term investments, dividends, capital gains or losses, and securities lending income) net of TSP administrative expenses.


The net expenses paid by investors is 0.042% or 4.2 basis points, which like all the TSP funds is ridiculously low and is a major benefit of the TSP. It cost $0.42 for each $1,000 invested.

How Should I Use the F Fund in my TSP Account?

In periods of falling interest rates, the F Fund will experience gains from the resulting rise in bond prices. So in the long run, you may expect F Fund returns to exceed those of the G Fund; however, you should also expect greater price volatility (up and down movements).

It is also important to know that higher returns are not guaranteed. This is because losses may occur when interest rates are rising, causing bond prices to fall.

The F Fund can be useful in a portfolio that also contains stocks funds. This is because the prices of bonds and stocks don’t always move in the same direction or by the same amount at the same time. So a retirement portfolio that contains stock funds, like the C, S, and I Funds, along with the F Fund, will tend to be less volatile than one that contains stock funds alone.

Advice from My Favorite Short Investing Book

Here is what my favorite investing book, The Elements of Investing: Easy Lessons for Every Investor, says about investment-grade bond index funds like the F Fund:

If indexing has advantages in the stock market, its superiority is even greater in the bond market. You would never want to hold just one bond (such as an IOU from General Motors or Chrysler) in your portfolio – any single bond issuer could get into financial deficiency and be unable to repay you in full. That’s why you need a broadly diversified portfolio of bonds – making a mutual fund essential. And it’s wise to use bond index funds: They have regularly proved superior to actively managed bond funds.

They also say, “Well-diversified portfolios should have holdings of bonds as well as stocks.”

If you want to know how to integrate the F fund into your own TSP investments, read the Crush the TSP series. In particular, step 3 tells you how to figure out how much of your portfolio to devote toward bonds.

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