Graham McCain · Alphaforge Research · Published Sep 28, 2026 · 3:52 pm ET · Revision 1
Scored over 5 trading sessions.
AI summary
The stock fell 10.1% to $193.05 on heavy volume after an 8-K announced the chief revenue officer will step down on October 1. The note views this as a significant single-session reaction, but emphasizes that the company's financial guidance from September 3 remains completely unchanged, with no numbers altered.
Historical data for similar events shows a wide five-session excess return range of -15.5% to +10.9%. The strongest counterpoint is that Friday's drop reclaimed a third of a recent 32.5% rally, suggesting that move was driven by positioning rather than fundamentals. The next checkpoint to assess the market's full reaction is the closing price on Monday, September 28.
Two paragraphs generated from the note. The authored note below is the record. Numbers only, no side.
1. The state
As of the 2026-09-25 close. Session 1 has closed.
Friday's close was $193.05, down 10.1% from a $214.64 prior close, 42.7% under the November 3, 2025 high of $336.99, and 41.3% above the close of 120 sessions ago. Volume was 1.95 times the recent norm, which the memory still files as ordinary, and $1.29 billion traded. The close sat at the bottom of the day's range.
2. What's new
On September 24 at 16:07 ET Zscaler filed an 8-K under Item 5.02: chief revenue officer Mike Rich steps down effective October 1, 2026, and Ross Tackett, head of worldwide sales, succeeds him the same day.
3. What that does to the state
Friday's filing does not replace the September 3 quarter.
300 similar days · 205 stocks · 251 sessions · 1h band
| Vs the market, in points | Low | Middle | High | Share up |
|---|
| 1 session | -8.5 | -0.6 | +5.0 | 40% |
| 5 sessions | -15.5 | -0.9 | +10.9 | 44% |
| 10 sessions | -19.1 | -2.6 | +19.6 | 40% |
The band is the prior close's neighborhood — what followed similar states as of the cutoff.
4. Same state, or a new one
Stayed in yesterday's neighborhood
Session 1 vs the market: +4.0. Prior-state 1-session range: -8.5 / -0.6 / +5.0.
A completed Monday close outside the 1-session band, a Zscaler filing that changes the first-quarter or fiscal 2027 guide, or a second departure from the sales organization would make Thursday's filing the needle.
Friday's close was $193.05, down 10.1% from a $214.64 prior close, on 6.67 million shares, 1.95 times the recent norm, and $1.29 billion of stock. The open was $206.00, the high $207.99, the low $192.74, and the close sat at the bottom of that range. The close is 42.7% under the 52-week high of $336.99 from November 3, 2025, and 41.3% above the close of 120 sessions ago.
The filing came Thursday at 16:07 ET. Mike Rich steps down as chief revenue officer effective October 1, 2026, for personal reasons, takes severance under the company's change of control and severance policy, and stays as a strategic advisor through December 31. Ross Tackett, head of worldwide sales for three years, becomes chief revenue officer the same day. The 8-K and the release name no change to the quarter, the pipeline, or the guide.
The last number is still September 3. Fourth-quarter revenue was $898.2 million, up 25%, annual recurring revenue $3,771 million, up 25%, with $246 million of net new ARR, and fiscal 2026 free cash flow $779.1 million, 23% of revenue. The guide for fiscal 2027 is revenue of $3.908 billion to $3.938 billion and ARR of $4.396 billion to $4.426 billion. From the September 8 close of $161.94 the stock rose 32.5% in twelve sessions to Thursday's $214.64 before Friday took 10.1% of it back. Until Monday's close, the exam is Friday's 5-session excess band, whose middle is -0.9%.
Other reading, tape, and sources
The other reading
A sales chief leaving five weeks into the fiscal first quarter, with an heir already running worldwide sales, is a personnel change, not a demand change, and the fiscal 2027 guide stands. The 32.5% run from September 8 into Thursday is the other reading: Friday took back a third of it on a filing with no number in it, which says how much of that run was position, not print.
What would change this
A completed Monday close outside the 1-session band, a Zscaler filing that changes the first-quarter or fiscal 2027 guide, or a second departure from the sales organization would make Thursday's filing the needle. A chief revenue officer change alone, with the guide intact, would not.
The tape
Friday's close was $193.05, down 10.1% from a $214.64 prior close, 42.7% under the November 3, 2025 high of $336.99, and 41.3% above the close of 120 sessions ago. Volume was 1.95 times the recent norm, which the memory still files as ordinary, and $1.29 billion traded. The close sat at the bottom of the day's range. Thursday had closed up 0.1% on 0.70 times normal volume, before the filing.
What was filed
On September 24 at 16:07 ET Zscaler filed an 8-K under Item 5.02: chief revenue officer Mike Rich steps down effective October 1, 2026, and Ross Tackett, head of worldwide sales, succeeds him the same day. The release gives personal reasons. Rich receives severance under the change of control and severance policy and stays as a strategic advisor through December 31, 2026. Neither document changes a number from the September 3 results or the fiscal 2027 guide.
The numbers around the move
Friday's filing does not replace the September 3 quarter. The 5-session excess band on Friday's state is -15.5 / -0.9 / +10.9 across 300 analogs, three times as wide as the base for this kind of session. A completed Monday close inside the 1-session band, -8.5 / +5.0 from $193.05, leaves this neighborhood in place.
What the stock did
Friday's close is the reaction to Thursday's filing: $193.05, down 10.1%, on 1.95 times recent volume, closed at the low of the range. Monday's close is not in. That close is the first test of whether the tape leaves Friday's neighborhood.
The comparison
Five-session excess -15.5 / -0.9 / +10.9 across 300 analogs on the 1-hour scale, with the up-share at 44%. One session -8.5 / -0.6 / +5.0. Ten sessions -19.1 / -2.6 / +19.6. The band is 2.9 times the base width, so the memory says the next week is wide, not which way. The comparisons are state and shape, not a forecast, and they imply no side.
Sources
Friday's tape and band are the September 25 state packet. The transition is the September 24 8-K and its exhibit 99.1, accepted at 16:07:41 ET. The quarter and the guide are the September 3 exhibit 99.1. The memory holds no September 3 session for ZS, so the report-day close is not quoted; the first session after the report, September 4, closed at $169.80 on 7.7 million shares. The September 8 to September 24 run is from stored daily closes.
- September 25 completed-session state packet for ZS · Available Sep 25, 2026 · 9:00 pm ET
- Zscaler 8-K, September 24, 2026: Item 5.02, chief revenue officer transition · Available Sep 24, 2026 · 4:07 pm ET
- Zscaler exhibit 99.1, September 24, 2026: Ross Tackett appointed chief revenue officer · Available Sep 24, 2026 · 4:07 pm ET
- Zscaler exhibit 99.1, September 3, 2026: fourth-quarter and fiscal 2026 results and fiscal 2027 guidance · Available Sep 3, 2026 · 4:08 pm ET