By David Enna, Tipswatch.com
Just about every week, I get a comment or question from readers worried about the dangers of buying a Treasury Inflation-Protected Security on the secondary market with a high (or even not-so-high) inflation index.
Why is that a potential problem? Because TIPS come with a deflation-fighting guarantee: At maturity, you cannot receive less than par value, even if the nation goes through a prolonged period of deflation. Buying a TIPS with a high inflation index means part of your investment is not guaranteed to be returned at maturity.
Here is what I think: It’s possible a period of low or negative inflation could mean your TIPS investments are going to under-perform nominal Treasurys. But, under most circumstances, you are highly unlikely to lose money on that investment if held to maturity.
Some things to consider:
It has never happened. TIPS have been issued since 1997 in 5-, 10-, 20- and 30-year maturities (the 20-year was discontinued in 2009). Over that time, no TIPS has matured with an inflation index of less than 1.000, meaning par value. So the “deflation guarantee” has never been triggered for a TIPS purchased at auction.
Inflation is the norm. Since 1971, the lowest average annual inflation for any 5-year period was 1.4%, for the 5 years ending in both 2017 and 2018. For 10-year periods, the lowest was 1.6%, for the years ending in 2017. For a 30-year period, the lowest was 2.2%, for the years ending in 2020.
So if you are buying a TIPS on the secondary market with a high inflation index and 5 years remaining to maturity, you can be fairly confident you won’t be struck by a 5 year period of deflation, eating away at your original investment.
The deflation risk is more pronounced if you buy a TIPS with a very short period (meaning months) remaining to maturity. The longer the term, the lower the potential risk.
Long-term deflation is rare. The United States has not recorded a single year of December-to-December deflation in 70 years. The last deflationary year was 1954, when prices declined by 0.7%. The lowest since then was 2008, when inflation increased 0.1.%
In this chart, I have recorded 1) at the top, deflationary years going back to 1929 along with corresponding Gross Domestic Product changes in each of those years, and 2) at the bottom, the years with positive inflation but negative GDP rates.
The most devastating period of deflation came in the Great Depression years of 1930 to 1933, when prices fell a cumulative 24% from January 1930 to December 1933. That decline was matched by a similar drop in GDP.
But since 1954, inflation continued to increase even when GDP growth was negative, resulting in some classic years of stagflation in 1974, 1975 and 1980. Since the 1980s, the Federal Reserve has taken a greater role in trying to tamp down recessions, possibly easing the effects of economic downturns and holding inflation higher.
In the Great Recession years of late 2007 to mid 2009, inflation continued climbing: rising 0.1% in 2008 and 2.7% in 2009, despite negative GDP growth in 2009.
And in the brief COVID recession of 2020, inflation still managed to climb 1.4% even as the economy faltered. The next year, in 2021, annual inflation rose to 7.0%.
Short-term deflation is a risk
As I noted, the shorter the time to maturity, the more a TIPS is at risk of deflation because TIPS inflation accruals are based on non-seasonally adjusted inflation, which often dips into deflation in the later months of the year.
This chart shows month-over-month declines in non-seasonally adjusted inflation, going back to 2012. Note that minor deflation is common in nearly every November and December, and is fairly common in July, August and October. But also note that the annual inflation rate for every year is positive, overcoming the late-year swoons.
So if you are looking to buy a TIPS maturing in April 2025, with just a few months remaining, realize that the TIPS is likely to be hit by deflation in at least two or three of the remaining months. Its final inflation index will be set by inflation in February 2025.
The market knows what’s likely ahead for the April 2025 TIPS, and its real yield is currently higher (3.576%) than that of a similar 5-year TIPS that will mature in October 2025 (2.739%). In other words, deflation presents more of a risk for the April TIPS than it does for the October TIPS, and the market has adjusted prices to reflect that.
Is the October 2025 TIPS (with an inflation index of 1.207) safer than the April 2025 TIPS (inflation index of 1.212). Who knows? Because both are short-term investments, they both have some deflation risk. The April issue has a bit more risk and is priced accordingly. More on this here.
I Bonds have an advantage
U.S. Series I Savings Bonds pay out a composite interest rate based on a permanent fixed rate (currently 1.3%) and a six-month variable rate (currently 2.96%). No matter what happens with the variable rate, the I Bond’s composite rate can never go below 0.0% and the principal can never decline. So I Bonds have rock-solid protection against deflation.
In addition, while TIPS lose principal during spells of deflation, the I Bond never loses value. When inflation starts rising again, the TIPS has to make up lost ground. The I Bond starts increasing from where it left off, a nice advantage over TIPS.
But, on the flip side, the I Bond’s fixed rate of 1.3% (equivalent to its real yield) is well below the 2.0%+ real yields currently found on all TIPS maturities.
Worst case scenario: Japan
I can’t claim to understand anything about Japan’s complex economy, but I know that both inflation and interest rates have been very low for more than two decades in that country. This is from the World Economic Forum:
Between 1960 and the late 1980s, Japan’s economic growth was double that of the US. But in 1989, there was a stock market crash and a banking crisis in Japan. Inflation in Japan has remained low ever since, and turned into deflation in the 2000s, and again during the pandemic.
After two decades of extremely accommodative monetary policy, Japan is now moving to bring interest rates out of the ultra-low (or negative) range. Annual inflation rose to 2.8% in May 2024, considered a positive trend.
In Japan, rising inflation is considered a positive, which isn’t true in the United States. It’s hard to say if this is an omen for the U.S., or just a singular problem for Japan.
Final thoughts
If you want to build a ladder of TIPS stretching out 20 to 30 years, you are going to have to accept buying additional principal that is not protected against deflation. The TIPS maturing in February 2040 has an inflation index of 1.448, meaning the investor will be buying about 45% of additional principal. Is that actually risky? Sure, there is a very slight possibility of deflation striking across the next 16 years. But not enough to worry about, in my opinion.
If you have been holding any long-term TIPS for many years, they all have inflation accruals that aren’t protected against deflation. I could be wrong, but I don’t think the deflation risk is high enough to abandon these investments.
For example, I own CUSIP 912810FH6 in a taxable account at TreasuryDirect, a long-ago 30-year TIPS purchase that will mature April 15, 2029. It has a coupon rate of 3.875% and an inflation index of 1.90508, meaning it has accrued principal 90.5% above par value.
Do I lose sleep at night worrying about deflation eating away at my principal? No. This TIPS is a great asset. (But today, if I were looking on the secondary market for a TIPS maturing in April 2029, I would not buy this one. I’d prefer the April 2029 TIPS that just had a reopening auction with a much lower inflation index.)
Accepting some deflation risk is part of investing in TIPS. That risk, as I have noted, is fairly minor in most scenarios.
• Now is an ideal time to build a TIPS ladder
• Confused by TIPS? Read my Q&A on TIPS
• TIPS in depth: Understand the language
• TIPS on the secondary market: Things to consider
• Upcoming schedule of TIPS auctions
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Follow Tipswatch on X (Twitter) for updates on daily Treasury auctions and real yield trends (when I am not traveling).
Feel free to post comments or questions below. If it is your first-ever comment, it will have to wait for moderation. After that, your comments will automatically appear.Please stay on topic and avoid political tirades.
David Enna is a financial journalist, not a financial adviser. He is not selling or profiting from any investment discussed. I Bonds and TIPS are not “get rich” investments; they are best used for capital preservation and inflation protection. They can be purchased through the Treasury or other providers without fees, commissions or carrying charges. Please do your own research before investing.


















Thank you! I will need to post something soon.