How to Track Sector Rotation With Relative Strength Charts

Plot a sector fund’s price by itself and you learn whether it went up. For rotation that tells you little. Divide the same fund by a broad index and the chart answers what you actually want to know, which is whether that part of the market has been doing better or worse than the market as a whole, and everything else in tracking rotation is built on that one ratio line.

Which funds do you chart?

One fund per sector of the GICS classification. GICS splits the market into 11 sectors, from energy and materials to utilities and real estate. Each has funds that track it. Pick funds built on the same index family where you can, because mixing providers can mean mixing slightly different definitions of what belongs in a sector, and the ratio lines then disagree for reasons unrelated to rotation.

For the benchmark, take a fund on a broad index such as the S&P 500. Keep it the same every week.

How do you build the ratio chart?

Most charting platforms accept one ticker divided by another. The result is a single line. Rising means the sector is beating the index. Falling means it is trailing, even in a week when both prices went up. That line is a relative strength line, and the relative strength ratios lesson builds one from scratch.

Put all 11 on one layout. Weekly bars are enough.

Ignore the level of each line. A ratio of 0.35 or 1.8 just reflects the two share prices and says nothing about strength. Direction and slope carry the information, so compare how steeply each line climbs or drops across a matching run of weeks.

How do you rank the sectors?

Take one-, three- and six-month returns for each fund and for the index. Subtract the index return from each sector’s. Here is a hypothetical three-month snapshot.

Technology leads by 6 points. Utilities lag by 5. The ratio line itself moves slightly less than the simple difference, since it divides one growth factor by the other, though the gap in points sorts the list in the same order. Repeat for the one- and six-month windows. A sector near the top of all three is a steadier leader than one that tops only the shortest.

The disagreements between windows are where rotation shows first. Say a hypothetical energy fund is up 4% over one month while the index is up 1%, so it leads by 3 points, yet over six months it is down 6% against an index up 5%, which leaves it 11 points behind. That mix is what an early turn looks like. The short window has flipped. The long one hasn’t. It could be the start of a new leader or a bounce inside a longer decline, and the ratio chart plus the breadth check are how you tell the two apart over the following weeks.

What does a turn look like?

Ratio lines turn before rankings do. A lagging sector’s line stops falling. It moves sideways for a few weeks. Then it starts making higher lows. A leader does the reverse, flattening and slipping while its price may still be climbing, which is exactly the pattern that fools anyone who watches only the price chart and assumes that a rising sector fund must still be a leading one. Mark those turns. The ranking confirms them later, once the longer windows catch up.

Is the whole sector moving?

Breadth tells you. A sector fund can rise because its largest holdings rallied while most of its other stocks went nowhere. That kind of leadership breaks easily. Check what share of the sector’s stocks trade above their own moving average. Or compare the market-weighted fund with an equal-weighted version of the same sector, if one exists. When both rise, the move is broad.

What do you do with the reading?

Shift the watchlist a little at a time. Look for stocks in the sectors whose ratio lines are rising. Drop names from sectors rolling over. Keep the old leaders on a secondary list for a while, since a sector whose line has flattened can resume its lead, and a quick return to strength is easier to catch if you haven’t deleted the names.

Ranking individual stocks is the next layer, covered in how to rank stocks by relative strength. The textbook sequence of sectors through a business cycle is questioned in the sector rotation model is tidier than any real cycle. The musical chairs for sectors course takes the whole process in order, and the swing trading hub has the rest.