The takeaway
iShares iBonds Dec 2031 Term Treasury ETF shows a moderate seasonal pattern over 5 years of data — strongest in November (+2.0%) and softest in October (−1.5%).
Right now
In July, the fund has risen 50% of years, averaging +1.2%, roughly 0.9 pts behind the S&P 500.
The full picture
iShares iBonds Dec 2031 Term Treasury ETF's most dependable month has been November, higher in 5 of 5 years; October has been its least reliable, up just 20% of the time.
| Year | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Win rate % | ||||||||||||
| Median return % | ||||||||||||
| 2025 | ||||||||||||
| 2024 | ||||||||||||
| 2023 | ||||||||||||
| 2022 | ||||||||||||
| 2021 | — | — | — | — | — | — | — |
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 2031 Term Treasury ETF’s average for a month minus the S&P 500’s average for that same month — isolating iShares iBonds Dec 2031 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 5 years — the pattern is holding.
Figures are the typical (median) November return and how often it rose — the last 5 years versus the last 5(the heatmap’s default window). This verdict stays anchored to that 5-year window even if you zoom the chart, so it never disagrees with the badges above.
In plain English
Strip the year back and a single month does the heavy lifting: November, up in all 5 Novembers while the other eleven tend to blur together.
Its average (+2.0%) and median (+1.3%) land within a hair of each other — the tell of steady, year-after-year gains rather than one outlier doing the work. It is among its calmest months, too, its returns swinging least from year to year (a 1.2% spread), and even its worst November in 5 years lost only 0.8% — the gentlest downside anywhere on its calendar. Set against the S&P 500, mind, November is close to a wash — the gain mirrors the market more than it beats it. That consistency sets it apart from the field, where the average stock manages November only about 62% of the time.
The strength clusters rather than stands alone — November–January forms a firm stretch that carries much of the year. The weaker half of the year is plainer: October has been the soft spot — the weakest of 5 months that average a loss (−1.5%), and the edge isn't year-round — the fund has trailed the S&P 500 in April, October, and September.
November has now closed higher 5 years running.
The takeaway is less about when to buy than what to expect: November aside, the fund's months offer little reliable tilt. With a short 5-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.
Yes, to a moderate degree. Since 2021 its best month (November, +2.0%) has run well ahead of its worst (October, −1.5%) — the heatmap above shows how steady that gap has been year to year.
November has been the strongest, averaging +2.0% and closing higher in all 5 years on record since 2021.
It's the weakest, averaging −1.5% — 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.
Before you trade