Should I buy short-term TIPS or just a regular TIPS fund?
TIPS, like other governmental bonds, have duration. Should you have short-term TIPS or a total or intermediate-term TIPS fund?
Interest rate sensitivity is something I bet of which you are aware, but how does that apply to TIPS? And TIPS duration? Do you want Short-Term TIPS?
Duration is a bond’s price sensitivity to interest rate changes. With treasury bonds, it measures the sensitivity to changes in nominal (before inflation) interest rates. For TIPS, it measures the sensitivity to changes in real (after inflation) interest rates. One doesn’t account for inflation expectations, and the other does!
Let’s dig into TIPS and duration to decide if you should buy short-duration TIPS or just a regular TIPS fund.
Short-Term Duration and TIPS
Duration can be defined as a complicated concept: it is a bond’s price sensitivity to interest rate changes.
Bond price and interest rates are like a teeter-totter; as one goes up, the other goes down. If the duration is short (the bond will pay out soon), there is not much change in price with changes in interest rates. On the other hand, if the duration is more prolonged, more minor changes in interest rates affect the price much more.
You cannot sell the bond you hold and buy a higher-yielding (new) bond when the interest rates increase. No one would pay you that much for your old, lower-yielding bond!
The longer the duration, the more the effect!
Said another way, short-term treasuries don’t change much in price when interest rate increases, whereas long-duration treasuries typically have much larger swings!
What about duration with TIPS? The same concept holds. If you own a TIPS fund (typically a mutual fund or an ETF), and you have increased interest rates, then the fund’s price goes down. Short duration has more minor changes, large duration—more extensive changes.
So now that we are (mostly) clear with duration, should you own short-term TIPS or intermediate-term TIPS?
Why Should You Own Intermediate-Term TIPS?
Intermediate-term TIPS, on average, pay more than short-term TIPS. This is true with other treasuries, as the longer you “give” your money to the government, the more you require in return.
TIPS Duration and Yield
Above, the yield (average coupon rate) depends on the TIPS duration for several different ETFs. In general, as TIPS duration increases, so does yield.
You should own intermediate-term (or longer) TIPS because the yield is higher than short-term TIPS.
Why Should You Own Short-Term TIPS?
Short-term TIPS yield less than longer-term TIPS. So why bother?
Vanguard seems to think that short-term TIPS correlate better with inflation. This is mentioned in a 2012 White Paper that no longer appears online in the USA. Luckily, you can find it here ( The long and short of TIPS ) on their Canadian site.
The long and the short: short-term TIPS hedge against inflation. Short-duration TIPS track CPI well, whereas their longer duration counterparts don’t because of volatility. Intermediate-term and long-term tips are just too sensitive to changes in real interest rates to provide a short-term hedge.
I note 2012 was when Vanguard added short-term TIPS to their pre-retirement glidepath, so this paper was their “just so” manifesto.
From their paper:
We found that the return on a short-term TIPS benchmark (of 0-to-5-year
maturities) has been more highly correlated to actual monthly and yearly
CPI (Consumer Price Index) inflation than other segments of the U.S. TIPS
market over the past decade. Although, in practice, all TIPS securities
receive the same CPI principal adjustment, short-term TIPS returns tend to most
closely track actual CPI inflation because of their lower duration and greater
responsiveness to temporary, unexpected inflation spikes.
While they note that short-term TIPS are more appropriate for risk-averse investors who want to tract the CPI, there is no free lunch.
Further from the paper:
Of course, the higher inflation correlation of short-term TIPS comes at a cost—
a lower expected income return versus that of the
broad TIPS market. In this sense, the risk−return trade-offs of investing in a
short-maturity versus a longer-maturity TIPS portfolio parallel those involved
when selecting the interest rate exposure of any other bond portfolio.
They conclude that the investor should decide if they care about short-term inflation or long-term purchasing power, positive inflation-adjusted (real) long-run returns. And, of course, the answer is “both” to Vanguard.
So, Which “Hedge” Inflation Better: Short-Term TIPS or Longer Duration TIPS?
So, which is a better hedge for inflation?
Volatility and Correlation to Inflation
Above, you can see a graph from the same white paper.
Note that blue is the correlation to inflation and tan is volatility.
Short-term TIPS correlate best to inflation with the lowest volatility. Gold has a reasonable hedging capacity, but at the cost of massive volatility.
Note that you decrease correlation and increase volatility with the intermediate and the long-term tips.
Thus, changing to short-duration TIPS means a higher correlation with inflation, lower volatility, AND a decrease in yields.
The Key: What WILL Inflation Be?
When considering TIPS, it is most important to remember that inflation expectations are already baked into the price.
Only UNEXPECTED inflation allows higher returns with TIPS. If there is only the inflation that the market expects there to be, TIPS will be priced the same as their other governmental bond cousins.
So, what will inflation be?
Above, you can see inflation changes in the US over almost 250 years.
Note that deflation was quite common before the 1940s but not since. Remember that the truth about inflation is that we tolerate it at modest levels because it is much better for everyone than deflation. Deflation is to be avoided at all costs, and it seems as if the Fed has done its job here quite well.
It is also interesting to note the inflation of the 1970s and the decrease in the trend since then.
What will inflation be? Who knows! But, the expectation of inflation sets TIPS prices, and short duration TIPS are a short-term Hedge against Unexpected inflation.
Short Term TIPS are a Short-Term Hedge Against Unexpected Inflation
Let’s look at expected inflation vs. unexpected inflation for a second.
Correlation of Asset Classes with Expected and Unexpected Inflation
You can see correlation to expected inflation, and on the bottom, correlation with unexpected inflation. This is from two different periods, but the main focus here is on the second to last box on the left.
Look at TIPS and Short-term TIPS with expected (top) and unexpected (bottom) inflation. Short-duration TIPS are more correlated with expected and unexpected inflation over both the long-term and recent history. Of course, it is interesting to know that TIPS haven’t been around for more than a couple of decades, so make what you will of the data!
Summary—Should I buy the short-term TIPS?
In summary, short-duration TIPS funds have a lower yield. There may be a higher correlation to unexpected short-term inflation than with longer-duration TIPS funds. Longer-term TIPS funds suffer from too much volatility to allow short-term inflation hedging.
It is interesting to think why this may be the case. After all, the price of TIPS depends on the expected inflation. So, if people believe there will be inflation, all TIPS become more expensive to buy.
Perhaps the difference in the duration and correlation with inflation is, in fact, an investor’s sentiments about inflation. Only investors’ concerns about inflation drive up the prices of TIPS. Over the long term, sentiment changes cause volatility due to sentiment alone.
Further, short-duration TIPS are less affected by increases in interest rates, as is the case with all bonds.
What this means to me: you probably need to liability-match your TIPS.
If you have a short-term need for inflation-protected cash, consider short-term TIPS to better hedge that liability.
If, on the other hand, you are sinking part of your “safe-money” into TIPS perchance inflation, in the long run, the extra yield (albeit not much!) of the longer duration TIPS is worth the volatility.
After all, investors should care more about correlation to unexpected inflation – expected inflation is already baked into current market prices.
Let me know when you expect unexpected inflation; I’ll tell you what sort of TIPS fund to buy.