The takeaway
iShares iBonds Dec 2028 Term Treasury ETF shows a slight seasonal lean over 6 years of data — strongest in November (+1.1%) and softest in October (−0.9%).
Right now
In July, the fund has risen 83% of years, averaging +1.0%, roughly 1.1 pts behind the S&P 500.
The full picture
iShares iBonds Dec 2028 Term Treasury ETF's most dependable month has been November, higher in 6 of 6 years; October has been its least reliable, up just 17% of the time.
| Year | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
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| Median return % | ||||||||||||
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| 2020 | — | — |
Month by month
Across the year the fund has stayed close to the S&P 500 — no single month stands out as a real edge.
“vs S&P” is iShares iBonds Dec 2028 Term Treasury ETF’s average for a month minus the S&P 500’s average for that same month — isolating iShares iBonds Dec 2028 Term Treasury ETF’s own seasonal edge from broad market drift.
Reality check
Over the last 5 years, November has closed higher 100% of the time versus 100% across the last 6 years — the pattern is holding.
Figures are the typical (median) November return and how often it rose — the last 5 years versus the last 6(the heatmap’s default window). This verdict stays anchored to that 6-year window even if you zoom the chart, so it never disagrees with the badges above.
In plain English
The seasonal story is really one month's story — November. It has closed higher in all 6 Novembers, a concentration the rest of the calendar can't touch.
The strength looks broad-based rather than freakish: its average (+1.1%) and median (+0.6%) sit close together, so no single blow-out year is flattering the figure. Few peers keep such company in November — the typical stock clears it just 62% of the time.
It doesn't stand entirely alone — January, April, and May have leaned firm as well, if less emphatically. The weaker half of the year is plainer: October has been the soft spot — the weakest of 4 months that average a loss (−0.9%), and the edge isn't year-round — the fund has trailed the S&P 500 in April, October, and November.
November has now closed higher 6 years running. Reassuringly, the tendency has held its shape: the recent five years still track the years behind them.
For a fund this dependable in November, the sharper question is the rest of the year — outside its strong stretch, the calendar gives far less to lean on. With a short 6-year record, the signal is best held loosely.
Short answers on the fund's best month (November), its worst (October), and whether it really trades seasonally.
Only mildly. The fund's months are fairly even — November is the firmest (+1.1%) and October the softest (−0.9%), a narrow spread that points to weak seasonality rather than a strong calendar effect.
November has been the strongest, averaging +1.1% and closing higher in all 6 years on record since 2020.
It's the weakest, averaging −0.9% — historically a soft spot, though it still varies from year to year.
Explore
These names have the strongest July track records on record — a starting point for comparison.
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