The takeaway
American Century ETF Trust shows a pronounced seasonal pattern over 3 years of data — strongest in May (+5.4%) and softest in April (−3.1%).
Right now
In July, the fund has risen 100% of years, averaging +1.9% — essentially in line with the S&P 500.
The full picture
American Century ETF Trust's most dependable month has been May, higher in 2 of 2 years; April has been its least reliable, up just 0% of the time.
| Year | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Win rate % | ||||||||||||
| Median return % | ||||||||||||
| 2025 | ||||||||||||
| 2024 | ||||||||||||
| 2023 | — | — | — | — | — | — | — | — |
Month by month
The fund's clearest edge over the S&P 500 lands in May (+4.7 pts); it has trailed the market most in April (−4.7 pts).
“vs S&P” is American Century ETF Trust’s average for a month minus the S&P 500’s average for that same month — isolating American Century ETF Trust’s own seasonal edge from broad market drift.
Reality check
Not enough recent May history to say whether the pattern still holds.
Figures are the typical (median) May return and how often it rose — the last 2 years versus the last 3(the heatmap’s default window). This verdict stays anchored to that 3-year window even if you zoom the chart, so it never disagrees with the badges above.
In plain English
This is a fund you can almost set a calendar by, and May is the anchor — it has closed higher in all 2 Mays, the steadiest beat on its year.
The strength looks broad-based rather than freakish: its average (+5.4%) and median (+5.4%) sit close together, so no single blow-out year is flattering the figure. Few months are steadier: May's returns vary by just 0.5% year to year, and even its worst May in 3 years lost only 4.9% — the gentlest downside anywhere on its calendar. Better still, that strength is the fund's own and not just a buoyant market — May has outpaced the S&P 500 by +4.7 points on average. Few peers keep such company in May — the typical stock clears it just 55% of the time.
May anchors a run, too: the May-through-January window has been the fund's reliable season. At the other end of the calendar, April has been the soft spot — the only month to average an outright loss (−3.1%), and the edge isn't year-round — the fund has trailed the S&P 500 in April, March, and October.
For a fund this dependable in May, the sharper question is the rest of the year — outside its strong stretch, the calendar gives far less to lean on. With a short 3-year record, the signal is best held loosely.
Short answers on the fund's best month (May), its worst (April), and whether it really trades seasonally.
Yes, to a pronounced degree. Since 2023 its best month (May, +5.4%) has run well ahead of its worst (April, −3.1%) — the heatmap above shows how steady that gap has been year to year.
May has been the strongest, averaging +5.4% and closing higher in all 2 years on record since 2023.
It's the weakest, averaging −3.1% — 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