How Low Can Your Bond Values Go?

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Bonds serve as a ballast to offset the volatility of stocks, particularly when stock values are falling. Since the start of the year, that’s exactly what stocks have done. So how are bonds holding up?

Chart representing bond prices falling

Vanguard’s Total Bond Market Index Fund (VBTLX) is a popular core bond holding for many, including me. As of May 6, this fund was already down 10.54% for the year. It lost nearly 4% in April alone, and nearly another 1% the first week of May.

The Federal Reserve is expected to continue hiking rates to fight inflation, meaning more losses for bond holders could be on the horizon.

Rising interest rates are driving the value of existing bonds lower. But what factors determine how much bond values drop when interest rates rise? How much more can bonds continue to lose?

Understanding Bond Duration and Interest Rate Risk

The relationship between interest rates and bond prices can be complicated. It’s easy to get lost in the weeds and be overwhelmed.

I’m going to start with the key information that everyone managing your own portfolio should grasp in order to adequately understand and manage your risk. This includes understanding the concept of bond duration.

If you are willing to invest a little bit of time to go deeper, it is wise to understand a few key mathematical factors that influence duration. 

If at any point the math gets to be more than you are interested in, skip to the end. I’ll discuss a few specific features that make certain bonds especially susceptible to interest rate risk while others completely sidestep this risk.

What Is Bond Duration?

Investopedia defines bond duration as “a measure of how long it takes, in years, for an investor to be repaid the bond’s price by the bond’s total cash flows.” What exactly does that mean?

In more practical terms, bond duration can be thought of as a measure of how sensitive a bond’s price is to changes in interest rates. A rule of thumb regarding duration is for every 1% change in interest rates, a bond’s value will change by approximately 1% for every year of duration.

So if a bond has a duration of 3 years and interest rates go up by 1%, then the bond’s value would decrease by approximately 3%. If a bond has a duration of 9 years and prevailing rates drop by .5%, the bond would increase in value by approximately 4.5%.

The longer a bond’s duration the greater a bond’s interest rate risk if rates rise. The flip side of this risk is the potential for reward. A bond with a longer duration has more upside for price appreciation if interest rates fall.

Bond Duration In Practice

As an example, let’s look at Vanguard’s Total Bond Market Index Fund (VBTLX), a popular core bond holding. Compare that to the Vanguard Short-Term Bond Index Fund (VBIRX) and the Vanguard Long-Term Bond Index Fund (VBLAX) , funds of similar quality bonds but with shorter and longer durations.

VBTLX has an average duration of 6.9 years. VBIRX has an average duration of 2.7 years. VBLAX has an average duration of 15.7 years.

chart comparing bond durations between funds

How did these funds perform over the first quarter of 2022 when interest rates were rising? As of May 6, the Total Bond Market Index Fund is down 10.54% year-to-date. Over the same time frame, the Short-Term Fund is down a little less than half as much, 4.63%. The Long-Term Fund, with the longest duration of the three, is down 21.11% for the year.

Using Duration to Assess and Manage Risk

Understanding duration, you can assess the risk of your bond investments. VBTLX has an average duration of 6.9 years. So for every additional 1% interest rates rise, you can expect to lose about 7% on an investment in this particular fund.

It is important to remember that over time, lower yielding bonds in the portfolio will be flushed out and replaced with new higher yielding bonds. As they do, the risk to reward profile for bonds will improve.

New bonds will compensate you with more yield. As yields rise, so does the potential for them to go back down, offering you potential future price appreciation.

Even if you are certain interest rates will continue going up or will start going back down, that information is of little value if you don’t also know the timing, rate, and magnitude of the changes.

Predicting the direction, amount, and timing of interest rate changes is incredibly hard. To control your risk, keep duration less than or equal to the time until you will need to sell your bond investments.

Mathematical Factors That Influence Duration

That is the basic bond duration information anyone investing in bonds should understand. To gain a deeper understanding, we need to explore a few mathematical concepts that impact bond duration.

These concepts will help to clarify factors that determine how bond prices are related to interest rate changes. This informs the amount of interest rate risk present with a bond investment.

Inverse Relationship Between Interest Rates and Bond Prices

Interest rates and bond prices are inversely correlated. This means when prevailing interest rates go up, existing bond prices decrease. When rates drop, existing bonds become more valuable. I covered this recently when discussing how rising interest rates impact bond investments.

To quickly recap, imagine purchasing a $1,000 bond with a coupon rate of 2%. If you hold the bond to maturity, you will receive $20 of annual payments until the bond matures. At that point, your $1,000 principal will be returned along with your final payment.

Now, imagine interest rates increase to 3%. Investors could buy a new $1,000 bond and receive $30 of interest annually instead of the $20 you are receiving. If you had to sell your bond, you would have to do so at some discount to the $1,000 face value. Otherwise, there would be no incentive to purchase your old lower yielding bond.

Conversely, if rates dropped to only 1%, someone purchasing a new bond would be paid only $10 interest annually. They would covet your bond yielding 2%. As such, it would be worth some premium above the $1,000 face value if you chose to sell it.

The Length of Time Until A Bond Matures Impacts Sensitivity to Price Changes

The shorter the life of the bond, the less a change in interest rates impacts the price. This relationship is not linear. The size of the bond’s discount or premium will decrease at an increasing rate as its life gets shorter.

Return to our example above of a $1,000 bond yielding 2%. Let’s add the assumption that the bond has a maturity of 10 years at the time it is purchased.

If rates on new bonds increased to 3% a few months after buying the bond, you would be stuck with your bond paying only 2% for the remainder of the 9 plus years. 

Now imagine prevailing rates stayed at 2% for most of the life of the bond, then went up to 3% a few months before the bond matured. You would have been receiving prevailing rates for over nine years. You would only be “missing out” on the potential higher interest on your final payment. At that time, your principal would be returned and you could reinvest it at higher rates.

In either event, rising interest rates are not good for existing bond holders. But in the first of these extreme examples you would be much worse off. This would be reflected by a much bigger hit to your bond’s price.

Inverse Relationship Between Coupon Rate and Duration

If the coupon rate of a bond is higher, its sensitivity to a change in rates will be less. Conversely, if a bond has a low coupon rate, it will be more sensitive to a change in interest rates.

Consider it this way. If a bond is paying 10% interest, and rates go up or down by .5% that represents only a 5% difference between your coupon rate and prevailing rates.

Compare this to a bond yielding 1%. The same .5% change in interest rates represents a 50% difference between your bond and the prevailing rates. The price of the lower yielding bond would be impacted more significantly by this equivalent change in rates.

Over the past decade interest rates have been low by historical standards. The response to the COVID pandemic drove them to all time lows. These low starting yields left bonds extremely sensitive when rates started increasing.

Related: Retiring With Extreme Low Interest Rates

Bond Convexity

We’ve established that a decrease in interest rates will lead to a rise in bond prices. An increase in interest rates causes an existing bond’s value to fall. But the prices do not change by an equal amount.

A bond’s price will increase by a greater amount for a given decrease in interest rates than it would fall given an equivalent increase in interest rates. This leads to what is known as bond price convexity.

This is simply a mathematical truth that I’m sharing for the sake of completeness in covering the factors that impact bond price. There isn’t a whole lot to do with this piece of information. Just understand this math quirk always works to a bond investor’s advantage.

Abnormal Interest Rate Risk

We’ve discussed the impact of changing interest rates on bond prices in general. But not all bonds are created equal.

Bonds With Increased Interest Rate Risk

Some bonds are callable, meaning that the borrower can pay back the debt early if they choose to do so. The most common example in which you are likely to invest, directly or indirectly, is mortgage backed securities (MBS).

MBS are securities backed by pools of mortgages bundled together and sold to investors. They make up a substantial portion of investible debt. As such they are a substantial portion of many bond funds. 

Some investors seek even more exposure to MBS when their yields look particularly attractive. However, most mortgages can be paid off early.

When rates are going down, people are more likely to refinance at better terms. As the lender (i.e. the bond holder), this effectively shortens your duration at a time you would most benefit by having a long duration.

When rates are rising, fewer people will pay their mortgage off early. This essentially increases your duration, sticking you with lower yields for longer. You would benefit from a shorter duration so you could get your money back sooner and reinvest at new higher prevailing rates.

It is important to be aware of this feature when considering your interest rate risk. If you want to limit interest rate risk, it is better to limit exposure to debt that is callable.

Bonds With No Interest Rate Risk

On the other extreme, some bonds are not marketable. This means they can not be sold on a secondary market. 

As such, they have no interest rate risk if rates rise. On the flip side, they also have no upside for price appreciation if interest rates fall.

An example that is getting a lot of press at the moment is I Bonds. I Bonds must be purchased directly through Treasury Direct, and they must be redeemed in the same manner for their face value.

Related: I Bonds vs. TIPS

So How Much More Will We Lose With Bonds?

This is the million dollar question that investors want to know. Unfortunately, no one can give you the answer without a crystal ball that can see how high rates will go and when they will stop rising. Given what we know about duration, we can make a reasonable estimate of the risks we are exposed to based on some assumptions.

Since the beginning of the year, rates have risen sharply. As of May 6th, the 5-year treasuries are paying 3.06%. A 10-year treasury yields 3.12%. This represents an increase of approximately 2% on the 10-year and 2.5% on the 5-year in just four months.

The median yield on a 5 year treasury is 3.43% and the mean is 3.74% historically. So let’s call it 3.5% on average. 

The median yield on a 10 year treasury is 3.81% and the mean is 4.50% historically. So let’s call it a little over 4% on average.

It seems reasonable to assume rates will reach these historical averages. If so, we’re looking at an additional 1+/-% increase in rates multiplied by the duration on your bonds to get a reasonable expectation of additional losses.

If this assumption on rate hikes holds true and you have bonds with a shorter duration, that’s not great. It is tolerable for most investors.

The all-time high rate on 5-year treasury is 8.77%. The 10-year has been as high as 15.32%. If we got anywhere near that interest rate environment and/or you hold bonds of longer durations, there is a potential for much greater losses.

It’s important to stay humble. We must acknowledge there is always the possibility that things improve more quickly than anticipated. Rates could stabilize or even start going back down more quickly than currently anticipated by many.

Proceed With Caution

Unfortunately, no one knows how this ends. Be wary of anyone who says they do. 

Understanding duration is valuable to help manage the risk that bonds in your portfolio are exposed to. Plan accordingly. Don’t take risks you can’t afford to lose with your investments, particularly with this portion of your portfolio that most people rely on for safety.

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[Chris Mamula used principles of traditional retirement planning, combined with creative lifestyle design, to retire from a career as a physical therapist at age 41. After poor experiences with the financial industry early in his professional life, he educated himself on investing and tax planning. After achieving financial independence, Chris began writing about wealth building, DIY investing, financial planning, early retirement, and lifestyle design at Can I Retire Yet? He is also the primary author of the book Choose FI: Your Blueprint to Financial Independence. Chris also does financial planning with individuals and couples at Abundo Wealth, a low-cost, advice-only financial planning firm with the mission of making quality financial advice available to populations for whom it was previously inaccessible. Chris has been featured on MarketWatch, Morningstar, U.S. News & World Report, and Business Insider. He has spoken at events including the Bogleheads and the American Institute of Certified Public Accountants annual conferences. Blog inquiries can be sent to chris@caniretireyet.com. Financial planning inquiries can be sent to chris@abundowealth.com]

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15 Comments

  1. Chris,
    Your discussion is centered on bond funds, and their problem is that the managers regularly trade bonds, which makes their NAV and yield vary. Investors can thus lose money when they sell, even with the term date bond funds. The problem is that these funds are mostly correlated with the stock market, as we’re seeing now: stocks are down and so are bonds.

    A practical solution is to invest in bonds directly. It’s not as scary as it sounds. While not as transparent as trading stocks, it’s gotten much better over the last decade. When investing directly in bonds, you know (1) the exact the yield you will get for the life of the bond, and (2) the exact date of redemption. So I don’t really care what the bond market is doing, I’m guaranteed my yield & interest payments, as well as my principal (as long of course as the issuer doesn’t go bankrupt). Investing in a diversified set of 10 bonds, all rated BBB or greater, is a great way to avoid the pitfalls of bond funds, and you save on fees to boot.

    Mike

    1. Mike,

      Bond funds and individual bonds function similarly enough that I feel comfortable using them interchangeably in these discussions. There are rare times, like in March 2020 when there is so much trading that a fund’s NAV may not reflect the bond’s actual value, but that is rare and short-lived. It is of little concern assuming you are not panic buying or selling large quantities of securities at one time.

      I, like most people I believe, don’t avoid individual bonds because they are “scary,” but because individual bonds are more of a hassle and they offer less diversification than a fund. The couple of basis points of expense ratio for a low cost index fund or ETF with massive diversification is a very fair price IHMO.

      Two key points where I disagree strongly with your comment.
      1.) You say stock and bond funds are mostly correlated. That is true at the moment, but correlations shift all the time. Bonds are losing value primarily because rates are rising, not because of anything happening in the stock market. Correlation is not the same as causation. If stocks go up as rates rise, bonds values will still decrease as a function of the rising rates and the correlation will become negative.

      2.) You point out that investors in a bond fund can “lose money when they sell.” Individual bond investors can lose money when they have to sell at a discount as well. I pointed that out in the article. You can avoid losing principal by not selling at a discount, but then you are stuck holding bonds with below market rates until the bond matures. That is just how bonds work, whether purchased individually or as part of a fund.

      Best,
      Chris

      1. Chris,
        We’ll have to agree to disagree, as there are two huge differences between a bond fund and a bond:

        1. Stability of yield
        The yield on a fund is constantly varying. Over the last few years they have gone significantly down (of course they can also rise). For someone looking for steady income, bonds offer certainty of yield until maturity.

        2. Preservation of capital:
        Bond funds never mature, so unless you want to pass on your funds to your heirs, you will sell someday. And there’s no way to know the price you will get. With a bond, you know exactly how much you will receive and on the exact date.

        After redemption of the bond, the investor is faced with re-investing. The yield will be different, but the investor can plan to make lifestyle adjustments ahead of time, or invest in something else. The bond fund holder has no say. The only possible advantage of a bond fund is diversification, but I think holding 10 bonds or so that are investment grade, with laddered maturities, offers plenty of diversification.

        Cheers!

        Mike

        1. Mike,

          Yes, agree to disagree. You make some valid points and I appreciate you taking the time to share your thoughts. I just don’t see the value proposition of taking the effort to buy bonds individually, but there is no “right” answer and there is nothing wrong with either approach IMHO.

          Best,
          Chris

        2. I’m with you Mike, I’m not the sharpest knife in the drawer so I like keeping it real simple and owning the actual bond that I will hold to maturity. I could care less what the mark to market pricing is, as it is not really relevant. I understand how Chris is trying to rationalize his position, but I hate bond funds…I tolerate bonds because I like the concept of staying wealthy since it is no longer necessary to swing for the fences to maintain our retirement lifestyle.

  2. Hi. A question. If the YTD return of VBTLX is -10.55 and the yield is 3.02, does that mean the actual YTD return of VBTLX in my portfolio is the net of those two, so -7.53?
    Thanks.

    1. Good question Nancy. Typically, a fund’s reported returns are total return. Total return is interest payments received (always a positive value) plus price appreciation or minus price decreases.

      Hope that clarifies,
      Chris

  3. Some folks weren’t hip to the probability of losing money with bond funds. Wouldn’t buying a five year TIPS from the Treasury give you the comfort of knowing that your investment would keep up with inflation, while not declining in value? I don’t understand the way that the interest is calculated throughout the 5 year period.

    1. Jerry,

      You can actually lose money with a TIPS fund. That’s because of two factors. TIPS do have interest rate risk the same as all marketable bonds, so as rates rise, prices drop. It’s also because the fixed rate on TIPS can be negative, which they have been recently, though they are now very close to 0%.

      I Bonds are different as I noted in the article because they don’t have interest rate risk (or potential for appreciation) because they aren’t traded on secondary markets. I didn’t point out in this article they also have a floor fixed rate of 0%, which has been giving them an advantage over TIPS which will go away if rates go positive.

      I go into detail on the difference between these bonds, including how interest is calculated on them, here: https://www.caniretireyet.com/i-bonds-vs-tips/

      Best,
      Chris

  4. Hi Chris,
    Thanks for the post, very insightful.
    I’m keeping the fixed part of my portfolio in cash right now as I was scared to enter in Bonds with the rates at 0%. Do you think that it makes sense to start building a position in Bonds (VBTLX) right now ? Maybe using DCA?
    KR,

    Mark

    1. Mark,

      I can’t give specific advice, but I will share my personal strategy. Please note, our personal strategy is shaped by the fact that my wife and I still have earned income coming in and so don’t have to draw very much from our portfolio.

      I have 25% of our portfolio in bonds and cash. I’ve always been concerned with inflation, so I have it split 10% VBTLX, 10% VAIPX (both of which have durations of 7 +/- years, and so still have a good bit of interest rate risk) and 5% cash. The only change we’ve made recently is to buy the max allowable allotment of IBonds over the past 2 years.

      If we were in a more traditional retirement scenario, I’d prefer to have more of our money in instruments with shorter durations, and likely a larger overall percentage of our portfolio in bonds if rates are higher. This strategy from Allan Roth seems appealing, though again I’d personally keep an allotment to TIPS/I Bonds in addition to his strategy. https://www.etf.com/sections/index-investor-corner/fixed-income-new-game-new-rules

      I hope that helps.

      Best,
      Chris

  5. Fidelity has 2 year CD rates at 2.8%. Why would anyone invest in bonds when you can buy CDs?

    1. Josie,

      There are a lot of reasons to not lock all your money in a 2 year CD at 2.8% vs buying bonds, including:
      -you may need your money in less than 2 years and not be able to get it or have to pay a penalty thus lowering your real yield,
      -you may need your money in greater than 2 years, in which case yields on bonds with longer durations are > 2.8%,
      -CD rates change all the time just like the rates on bonds. If you used this strategy just a few months ago you couldn’t have gotten those rates and your money would be locked up. If you wait a few months they could be higher again,
      -2.8% is far less than the current inflation rate, meaning in real terms you are losing money.

      To be clear, I’m not saying there is anything wrong with buying CDs for money that you will likely need at the time. I am saying that your suggestion isn’t a no brainer decision as you seem to imply unless I’m reading your question incorrectly.

      Best,
      Chris

  6. Chris,, “How did these funds perform over the first quarter of 2021″ Did you mean 2022?
    ” it is better to limit exposure to debt that is callable.” Did you mean “Reduce” or “Avoid” callable debt?

    All the best!
    -JT-

    1. Oops, yes I guess I’m off a year. Embarrassing! Correction made. Thanks for pointing that out.

      On your second point, I’m not seeing the difference between the two.

Comments are closed.