The takeaway
Telephone and Data Systems Inc shows a pronounced seasonal pattern over 10 years of data — strongest in August (+19.8%) and softest in September (−5.5%).
Right now
In July, the stock has risen 50% of years, averaging +0.4%, roughly 1.7 pts behind the S&P 500.
The full picture
Telephone and Data Systems Inc's most dependable month has been August, higher in 8 of 10 years; September 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 August (+19.5 pts); it has trailed the market most in February (−5.6 pts).
“vs S&P” is Telephone and Data Systems Inc’s average for a month minus the S&P 500’s average for that same month — isolating Telephone and Data Systems Inc’s own seasonal edge from broad market drift.
Reality check
Over the last 5 years, August has closed higher 100% of the time versus 80% across the last 10 years — the pattern is strengthening.
Figures are the typical (median) August 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
Dependability is the through-line here. August stands out, higher in 8 of 10 Augusts, but it heads a clutch of months that pull the year reliably upward.
The headline flatters a touch — its +19.8% average sits well above the +3.5% a typical year delivers, the work of a few big Augusts. That reliability comes with real swings, mind — even August ranges by 51.6% from year to year, so any single year can land far from the average. Crucially, the gain is the stock's own rather than a rising tide's: August has cleared the S&P 500 by +19.5 points above the index. That consistency sets it apart from the field, where the average stock manages August only about 52% of the time.
A few other months pull their weight: January, October, and November have also closed higher more often than not. The weaker half of the year is plainer: September has been the soft spot — the weakest of 3 months that average a loss (−5.5%), and the edge isn't year-round — the stock has trailed the S&P 500 in February, September, and July. Its roughest month on record was a −37.6% November in 2022 — a reminder of how hard even a seasonal name can fall.
August has now closed higher 6 years running. If anything it has sharpened recently — the last five Augusts run ahead of the earlier years.
The takeaway is less about when to buy than what to expect: August aside, the stock's months offer little reliable tilt. With returns that swing hard year to year, the signal is best held loosely.
Short answers on the stock's best month (August), its worst (September), and whether it really trades seasonally.
Yes, to a pronounced degree. Since 2016 its best month (August, +19.8%) has run well ahead of its worst (September, −5.5%) — the heatmap above shows how steady that gap has been year to year.
August has been the strongest, averaging +19.8% and closing higher in 8 of 10 years since 2016.
It's the weakest, averaging −5.5% — 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