1 · One number+9.13% vs. −0.68%
+9.13% : −0.68%Energy ETF (XLE) Nov–Apr average vs. May–Oct average27 observations each, 1999–2025 · price basis, excluding distributions
Cutting the returns of the US energy sector ETF (XLE) into half-years since 1999, the Nov–Apr average was +9.13% and the May–Oct average was −0.68%. The materials sector ETF (XLB) had the same shape, +7.63% versus −1.08%. In both industries, most of the yearly return was concentrated in the winter-and-spring half of the year.
Over the same period the S&P 500 returned +4.99% in Nov–Apr and +2.43% in May–Oct. This means the six-month cycle from Lesson 2 was mild for the whole market, but split by industry, steeper and reversed cases were mixed in.
Quick check"Energy stocks rise in Nov–Apr" versus "In 27 observations in 1999–2025, XLE's Nov–Apr average was +9.13%." What is the difference?
The first is a prediction, the second is a record. The second sentence carries the period (1999–2025) and the sample size (27), which also reveals that the average was high, not that it was so every year.
2 · InsightEach industry has its own working season
Picture a four-season clothing store. Padded jackets sell in winter, swimsuits in summer. Even if the store's total sales are similar year-round, each item has its own peak. The stock market is similar. Even if the whole market's seasonality is mild, industries tied to real demand each have a different calendar.
The person who turned this idea into an investing rule is Sam Stovall, chief investment strategist at CFRA. His holds such as consumer discretionary, industrials, materials and IT in Nov–Apr, and such as consumer staples and health care in May–Oct, changing only the industry without leaving stocks. CFRA data put the S&P 500's six-month averages since 1945 at +6.6% for Nov–Apr and +1.4% for May–Oct (CFRA-Stovall, 2019).
The reason industry seasonality is easier to explain than whole-market seasonality is that the cause lies in . There is demand that returns at the same time each year: energy demand ahead of winter heating and the spring driving season, corporate capex plans bunched at the start of the year, and retail sales in the year-end shopping season. The general explanation is that stock prices reflect those expectations a few months before the actual demand. But this is an explanation, not a proven causal link, so this lesson treats it as a hypothesis.
The one-year calendar of real demand
Energy demandCapex and industryConsumption and retailPhysical gold demand
Tap a month. You'll see the real demand concentrated in that month and the related industries.
Demand timing by industry summarizes common explanations (a hypothesis). The Lunar New Year and Diwali follow the lunar and Hindu calendars, so their dates differ a little each year.
Recalling the principle from Lesson 4, industry seasonality belongs to the kind where you can write 'why it happens' in one line. So it may hold up longer than a price pattern with no cause, but when the size and timing of demand change, the pattern changes too. The shale revolution changed the structure of crude oil supply, and electric vehicles and remote work are changing what the driving season means.
Quick checkHow does Stovall's approach differ from Lesson 2's 'expected returns were lower in May–Oct'?
Stovall doesn't leave stocks. Six-month switching moves to bonds or cash in May–Oct, but the half-year rotation swaps between cyclical and defensive sectors within stocks.
3 · DataThe scorecard of nine sectors and gold
The nine Select Sector SPDR ETFs were listed in December 1998. So the half-year comparison covers 27 observations each, from May–Oct 1999 to May–Oct 2025, and for Nov–Apr from Nov 1999–Apr 2000 to Nov 2025–Apr 2026. In the chart below, the blue dot is the Nov–Apr average and the gray dot is the May–Oct average. The farther apart the two dots, the more that industry's return was concentrated in one half of the year.
Half-year average returns of nine sector ETFs
Nov–Apr averageMay–Oct average
Tap a row. You'll see the average, median, win rate and excess return versus the S&P 500.
Calculated directly from Yahoo Finance month-end closes for nine Select Sector SPDR ETFs and ^GSPC (price basis, excluding distributions and costs). 27 observations each, 1999–2025; the last Nov–Apr observation is Nov 2025–Apr 2026. Retrieved 2026-10-09.
The industries with the largest gaps were energy (+9.82 percentage points) and materials (+8.71), followed by industrials (+5.56). The cyclical sectors Stovall picks for Nov–Apr gathered at the top. But the picture changes a little when you also look at win rates. Energy's Nov–Apr win rate was 70% (19 of 27), actually lower than the S&P 500's (74%), and its May–Oct median was +0.07%, higher than the average (−0.68%). This means a few years of big collapses, like 2008, dragged down the summer average.
When comparing industries, matters more than absolute return. In a half-year when the whole market rises together, most industries are positive. Energy's Nov–Apr excess return (vs. the S&P 500) averaged +4.14 percentage points, but it beat the market in only 14 of 27 cases. The large average excess return came from a few big wins; it did not win every time.
| Sector ETF | Nov–Apr average | May–Oct average | Gap | Nov–Apr edge vs. the market |
| Energy (XLE) | +9.13% | −0.68% | +9.82%p | 14 of 27 |
| Materials (XLB) | +7.63% | −1.08% | +8.71%p | 19 of 27 |
| Industrials (XLI) | +6.95% | +1.38% | +5.56%p | 19 of 27 |
| Technology (XLK) | +4.91% | +5.48% | −0.57%p | 12 of 27 |
| S&P 500 | +4.99% | +2.43% | +2.56%p | (baseline) |
Commodities, not just industries, have calendars too. Calculating gold futures' (GC=F) monthly record from 2001 to September 2026 (25–26 observations per month), January's average of +2.95% (65% win rate) and August's +2.50% (73%) were high, and June was lowest at −0.87% (42%). The explanation often given is physical demand for precious metals ahead of the Chinese Lunar New Year and India's Diwali and wedding season. Brooke Thackray explains that the strength before the Lunar New Year has been clearer in the last 20 years (Wealth Professional, 2023-09-20).
Monthly record of gold futures
Tap a bar.
Calculated directly from Yahoo Finance GC=F (front-month continuous futures) month-end closes. January 2001 to September 2026; 26 observations for Jan–Sep and 25 for Oct–Dec. Continuous futures prices can differ slightly from the spot price because of contract rollovers.
Remember that the gold figures were calculated from a . Price gaps created when the front-month contract rolls to the next one at each expiry get mixed into the monthly returns. For gold the gap is small, but for commodities with high storage costs, like crude oil and natural gas, this distortion is large, so the same method should not be used.
Quick checkEnergy's Nov–Apr average excess return is +4.14 percentage points, yet it beat the market in only 14 of 27 years. How should you read this?
The average is a number made by a few big wins. Winning and losing years were nearly half and half, and the winning years had larger margins. You shouldn't say 'energy beats the market in winter' from the average alone; read it together with the win rate.
4 · TwistTech is the exception, and defensives broke too
Twist. Of the nine sectors, only tech (XLK) had a May–Oct average (+5.48%) higher than its Nov–Apr average (+4.91%). And the textbook rule "defensives in summer" missed by a wide margin over the last seven years.
Tech's status as the exception owes a lot to the last few years. XLK's May–Oct average was +2.46% in 1999–2018 but +14.11% in 2019–2025. In the period when big tech led the market, earnings growth and interest rates were a bigger force than the season.
May–Oct average, split by period
May–Oct average return (%). 20 observations for 1999–2018, 7 for 2019–2025. Calculated directly from Yahoo Finance month-end closes, price basis.
Consumer staples broke in the opposite direction. The consumer staples ETF (XLP)'s May–Oct average was +2.28% in 1999–2018, ahead of the S&P 500 (+0.48%), but in 2019–2025 it was −0.58%, far behind the S&P 500 (+7.99%). The difference from the −0.59% in the plan is rounding. The sample of 7 is small, but it is clear that the rule of using defensives as a summer refuge carried a large opportunity cost recently.
Common misconceptions
"When November comes, just switch to an energy ETF?" Since 1999, energy beat the market in Nov–Apr in 14 of 27 years. Bigger forces, such as oil prices, OPEC+ decisions and the economy, often pushed the season aside.
"Defensives are safe in summer?" In May–Oct 2019–2025, consumer staples averaged −0.58%, trailing the market by more than 8 percentage points. Defensives can reduce losses, but they carry an opportunity cost.
"Just buy gold in January?" A 65% win rate in January means that 9 of 26 were negative. Gold is more affected by real interest rates and the dollar (Learn (Economics): Why does gold rise when people are anxious?).
Quick checkIs tech's strength in May–Oct 2019–2025 a 'new seasonality'?
It's too early to call it seasonality. The sample is only 7, and in the same period tech was strong all year round. If the cause can't be explained by the season, then, following the principle of Lesson 4, don't use it as a basis for trading.
5 · One thing to practiceThe sector half-year table and excess return
Today's assignment is to build a half-year return table for nine sector ETFs and calculate the excess return versus the S&P 500. The table below is pre-calculated from the same data. Move the start and end years and the table is recalculated; tap a row to see that sector's year-by-year record. Keep only the sectors that lean the same way even when you change the period as candidates for 'seasonality with a cause.'
Narrowing to the last 10 years, you can check for yourself whether the Nov–Apr edge of materials and industrials remains and how much energy's gap has narrowed. Also remember that for sectors with large distributions, such as consumer staples and utilities, price-basis figures come out lower than actual returns. This table is an educational calculation and does not recommend trading any particular sector or ETF.
The figures in this lesson are on a price basis, so distributions, trading costs and taxes are excluded. A strategy of switching sectors every half-year loses its edge once trading costs and taxes add up. The fact that things leaned one way in the past is no guarantee they will lean the same way going forward.
Quick checkA sector that was strong in Nov–Apr over the full period was also strong over the last 10 years. What do you check next?
The cause and the win rate. Check whether that seasonality can be explained by real demand, and whether it is not just a high average but also beat the market in more than half the years. It has to pass both to become a filter candidate.
The one sentence left from Lesson 5Energy in winter, tech the exception