The takeaway
Builders FirstSource Inc shows a pronounced seasonal pattern over 10 years of data — strongest in November (+9.4%) and softest in October (−4.4%).
Right now
In July, the stock has risen 90% of years, averaging +8.4%, about +6.3 pts better than the S&P 500.
The full picture
Builders FirstSource Inc's most dependable month has been November, higher in 9 of 10 years; October has been its least reliable, up just 40% of the time.
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Month by month
The stock's clearest edge over the S&P 500 lands in November (+7.1 pts); it has trailed the market most in October (−5.4 pts).
“vs S&P” is Builders FirstSource Inc’s average for a month minus the S&P 500’s average for that same month — isolating Builders FirstSource Inc’s own seasonal edge from broad market drift.
Reality check
Over the last 5 years, November has closed higher 80% of the time versus 90% 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 9 of 10 Novembers, the steadiest beat on its year.
The strength looks broad-based rather than freakish: its average (+9.4%) and median (+10.8%) sit close together, so no single blow-out year is flattering the figure. No month is steadier: November's returns vary by just 6.0% year to year, and even its worst November in 10 years lost only 0.7% — the gentlest downside anywhere on its calendar. Better still, that strength is the stock's own and not just a buoyant market — November has outpaced the S&P 500 by +7.1 points on average. Few peers keep such company in November — the typical stock clears it just 62% of the time.
It doesn't stand entirely alone — February, July, and August have leaned firm as well, if less emphatically. On the other side of the ledger, October has been the soft spot — the weakest of 3 months that average a loss (−4.4%), and the edge isn't year-round — the stock has trailed the S&P 500 in October, March, and September. Its roughest month on record was a −49.4% March in 2020 — a reminder of how hard even a seasonal name can fall.
One run worth flagging just ended: a 9-year streak of positive Novembers was snapped by a −0.7% close in 2025. 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. With returns that swing hard year to year, the signal is best held loosely.
Short answers on the stock's best month (November), its worst (October), and whether it really trades seasonally.
Yes, to a pronounced degree. Since 2016 its best month (November, +9.4%) has run well ahead of its worst (October, −4.4%) — the heatmap above shows how steady that gap has been year to year.
November has been the strongest, averaging +9.4% and closing higher in 9 of 10 years since 2016.
It's the weakest, averaging −4.4% — 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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