The takeaway
ChipMOS Technologies Inc shows a moderate seasonal pattern over 10 years of data — strongest in November (+5.2%) and softest in April (−2.2%).
Right now
In July, the stock has risen 40% of years, averaging +0.5%, roughly 1.6 pts behind the S&P 500.
The full picture
ChipMOS Technologies Inc's most dependable month has been November, higher in 7 of 10 years; April has been its least reliable, up just 20% of the time.
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Month by month
The stock's clearest edge over the S&P 500 lands in May (+3.4 pts); it has trailed the market most in April (−3.9 pts).
“vs S&P” is ChipMOS Technologies Inc’s average for a month minus the S&P 500’s average for that same month — isolating ChipMOS Technologies Inc’s own seasonal edge from broad market drift.
Reality check
Over the last 5 years, November has closed higher 60% of the time versus 70% across the last 10 years — the pattern is weakening.
Figures are the typical (median) November return and how often it rose — the last 5 years versus the last 10(the heatmap’s default window). This verdict stays anchored to that 10-year window even if you zoom the chart, so it never disagrees with the badges above.
In plain English
This is a stock you can almost set a calendar by, and November is the anchor — it has closed higher in 7 of 10 Novembers, the steadiest beat on its year.
The strength looks broad-based rather than freakish: its average (+5.2%) and median (+6.3%) sit close together, so no single blow-out year is flattering the figure. That reliability comes with real swings, mind — even November ranges by 10.7% from year to year, so any single year can land far from the average. Better still, that strength is the stock's own and not just a buoyant market — November has outpaced the S&P 500 by +2.9 points on average. Some of that is a strong month market-wide, mind — November rises for about 62% of stocks — so the tendency is real if not unique.
November anchors a run, too: the September-through-November window has been the stock's reliable season. On the other side of the ledger, April has been the soft spot — the weakest of 3 months that average a loss (−2.2%), and the edge isn't year-round — the stock has trailed the S&P 500 in April, July, and December. Its roughest month on record was a −21.3% September in 2021 — a reminder of how hard even a seasonal name can fall.
The pattern has softened of late, November's last five years slipping below its longer-run record.
For a stock 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.
Short answers on the stock's best month (November), its worst (April), and whether it really trades seasonally.
Yes, to a moderate degree. Since 2016 its best month (November, +5.2%) has run well ahead of its worst (April, −2.2%) — the heatmap above shows how steady that gap has been year to year.
November has been the strongest, averaging +5.2% and closing higher in 7 of 10 years since 2016.
It's the weakest, averaging −2.2% — 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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