Lesson 2 of 6
A margin step and how to explain it
A gross margin that moves in a step has a short list of possible causes, and the filing distinguishes them without asserting which one applies.
By Javier Sanz
Founder of ValueScreener. Built Ninety Nine, a securities services provider, and sold it to a tier-one global bank; ran operations and internationalization at Alpaca, the brokerage API.
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In one minute
- A drift has many small causes; a step has one, and the test for which is a step is mechanical: do the earlier and later ranges overlap.
- The usual candidates are five: mix, price including currency, input cost, volume, and reclassification, and a filing can distinguish them.
- Look for the row that did not move. It bounds the explanations for the one that did.
Apple's gross margin sat between 37.82 and 39.08 percent in fiscal 2016 through 2020, and between 41.78 and 46.91 percent in fiscal 2021 through 2025, with no year in this ten-year archive in between. That is a step, not a drift, and the two are diagnosed differently. Nothing below asserts what caused it; a filing narrows the cause with documents already public.
Gross margin against operating margin, ten filed fiscal years
- Gross margin
- Operating margin
Show the numbers
| Gross margin | Operating margin | |
|---|---|---|
| FY16 | 39.08% | 27.84% |
| FY17 | 38.47% | 26.76% |
| FY18 | 38.34% | 26.69% |
| FY19 | 37.82% | 24.57% |
| FY20 | 38.23% | 24.15% |
| FY21 | 41.78% | 29.78% |
| FY22 | 43.31% | 30.29% |
| FY23 | 44.13% | 29.82% |
| FY24 | 46.21% | 31.51% |
| FY25 | 46.91% | 31.97% |
Step against drift
A drift is a run of small changes in one direction, usually with many small causes and no single year worth interrogating. A step is a discontinuity: take the range of the earlier regime and the range of the later one, and ask whether any year falls in the gap. Here none does, within this archive. For a drift you read a decade of management discussion looking for a theme; for a step you read two filings, the year before and the year after, side by side.
Five candidates, and what tells them apart
| Cause | What else moves | Where the filing shows it |
|---|---|---|
| Sales mix | Revenue shifts toward a higher or lower margin line, with no line's own margin changing | The products and services lines on the face of the statement of operations, Item 8 |
| Price, including currency | Realised prices move, in the reporting currency or from translating foreign sales | Item 7 usually names a price or currency effect directly |
| Input cost | Components, freight or labour move in cost of sales | The margin should move back when the cost does |
| Volume | Fixed costs in cost of sales spread over more or fewer units as revenue moves | Read alongside the revenue growth row |
| Reclassification | A cost moves between cost of sales and operating expenses | The accounting policies note in Item 8 |
The row that did not move, tested
Operating margin stepped too, from a 24.15 to 27.84 percent range in fiscal 2016 to 2020 to a 29.78 to 31.97 percent range from 2021 on, at the same boundary. A pure reclassification between cost of sales and operating expenses would move the gross line and leave the operating line alone, since both cost buckets sit above it. A step that shows up in both is not, on its own, consistent with reclassification alone. The general technique is not looking for the row that moved; it is looking for the row that did not, because the subtotal that stayed put bounds the explanations for the one that changed.
Net margin is the weakest of the three for this. It carries the tax charge. The Tax Cuts and Jobs Act of 2017 forced a one-time remeasurement of deferred tax balances that many companies booked in fiscal 2017 or 2018, with nothing to do with operations.
What the revenue path rules out
Revenue fell in two of the nine years this table can measure, fiscal 2019 and fiscal 2023. Gross margin fell in the first year and rose in the second, opposite directions on two declining-revenue years. That rules out the simplest version of the volume story, fixed costs in cost of sales spread over fewer units, though not a more careful version of it.
Do it on the FY2020 and FY2021 10-Ks
- Read Item 7's gross margin discussion in both filings and write down every cause it names.
- Take products and services net sales and cost of sales from the face of the statement of operations in both years, and compute each line's own gross margin.
- Compare whether the revenue mix between products and services moved enough to explain the change, or whether it was each line's own margin that moved instead.
Check yourself
Gross margin and operating margin step at the same boundary, in the same direction. What does that make less likely on its own?
- A change in sales mix
- A change in input cost
- A pure reclassification between cost of sales and operating expenses
Show the answer
Answer: C.
A reclassification across that boundary moves the gross line and leaves the operating line alone, since both cost buckets sit above it. A step in both together points somewhere else.Why is net margin the weakest of the three margins for diagnosing an operating-driven step?
- It is rounded more coarsely
- It carries the tax charge, which can move for reasons unrelated to operations
- It is not disclosed every year
Show the answer
Answer: B.
The 2017 tax law change forced a one-time remeasurement many companies booked in fiscal 2017 or 2018, unrelated to how the business performed that year.Revenue fell in two separate fiscal years, and gross margin moved in opposite directions in those two years. What does that rule out?
- That input costs ever changed
- The simplest version of the volume story, that fixed costs in cost of sales spread over more or fewer units as revenue moves
- That a reclassification ever happened
Show the answer
Answer: B.
If falling revenue always meant a lower margin through fixed-cost leverage, both declining years would have moved the same way. They did not.Sources
- Apple Inc., annual reports on Form 10-K, fiscal years 2012, 2015, 2020 and 2021, accession numbers in "Ten years in one table" for 2020 and 2021.
- Segment reporting, ASC 280: operating segments are reported as management reviews the business, and prior periods are restated when the segmentation changes.
- The Tax Cuts and Jobs Act of 2017 forced a one-time remeasurement of deferred tax balances, a structural fact stated without further attribution.
What this leaves out
- This lesson does not say what caused the step it describes. It sets out five candidate causes and the documents that distinguish them, and stops there.
- The ranges quoted come from the fiscal 2016 to 2025 10-Ks; a wider archive can and does read the same years differently, as the callout above shows.
- Nothing here is a view on Apple or on any security, and none of it describes what any margin will do next.