December returns aren't meaningfully different from any other month
Some investment professions are advising investors to wait until the end of the year to sell U.S. Treasury bond holdings. They point to bond-friendly year-end seasonal trends as their reasoning - but don't bank on it.
A year-end bounce would be welcome indeed to Treasury bond investors, since long-term Treasurys are down about 10% in just the past two months (using the Vanguard Long-Term Treasury ETF VGLT as a proxy).
History suggests that you shouldn't count on a year-end Treasury-market bounce, for two reasons.
First, positive year-end Treasury bond seasonality is a relatively recent phenomenon. The iShares 20+ Year Treasury Bond ETF TLT, for example, didn't begin trading until 2002. Long-term Treasurys' positive seasonality disappears when focusing on prior decades.
That said, there might be good theoretical reasons for why the past two decades for Treasurys are fundamentally different in ways that make the older history less relevant.
For more insight into this possibility, I reached out to Lisa Kramer, a finance professor at the University of Toronto who has extensively researched seasonal tendencies in the stock and bond markets, both in the U.S. as well as around the world. In an email, she said she isn't aware "of any structural/theoretical reason to put more weight on the later period."
The most obvious start date for any analysis of bond-market seasonality is 1952. That's when, according to a study that Kramer co-authored, "an accord between the U.S. Federal Reserve Board and the U.S. Treasury permitted interest rates to respond more freely to market forces." Prior to 1952, in contrast, interest rates were almost constant.
Since 1952, according to my analysis of the Ibbotson database (now part of investment researcher Morningstar), long-maturity U.S. Treasury bonds have produced an average total return of 0.59% during the month of December, versus an average of 0.49% for the other 11 months of the calendar. This difference is not significant at the 95% confidence level that statisticians often use when determining if a pattern is genuine.
The second reason it's ill-advised to count on a year-end Treasury bounce is that, even for the past two decades during which there is positive year-end Treasury seasonality, the statistical strength of that seasonality is miniscule. Consider the correlation since 2002 between the months of the year and long-term Treasurys' average return. The investment's "r-squared" is less than 1%, meaning that year-end seasonality explains less than 1% of the difference between December and other months of the year.
Any positive seasonality, even if it existed, would be overwhelmed by myriad other factors that influence Treasury returns. So if you believe that long-maturity Treasurys are poor investments at current prices, don't wait to sell.
Mark Hulbert is a regular contributor to MarketWatch. His Hulbert Ratings tracks investment newsletters that pay a flat fee to be audited. He can be reached at [email protected]
More: Why one technical analyst sees a 'tactical opportunity' in Treasurys
Plus: The S&P 500 is inflated by 25% because investors don't care about fundamentals
-Mark Hulbert
This content was created by MarketWatch, which is operated by Dow Jones & Co. MarketWatch is published independently from Dow Jones Newswires and The Wall Street Journal.