Graham McCain · Alphaforge Research · Published Sep 28, 2026 · 4:01 pm ET · Revision 1
Scored over 5 trading sessions.
AI summary
MongoDB's CEO resigned Monday morning to join Meta, causing the stock to open 24% lower at $311.75. The company reaffirmed its financial guidance and kept its investor day scheduled for Tuesday. The note views this as a leadership repricing, not a change in business fundamentals, with the opening price falling outside all historical bands based on Friday's trading state.
For similar past sessions, the historical five-session range was -11.4% to +9.8%. The strongest alternative reading is that the recent stock run-up had not accounted for the risk of the CEO departing so soon. The next checkpoint is Tuesday's close, which will be the first test of this new trading state.
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 $410.44, down 2.6% from a $421.40 prior close, 13.2% under the August 14 high of $473.10, 62.2% above the close of 120 sessions ago, and 19.1% above its 200-day. Volume was 0.71 times the recent norm and $555 million traded. The close sat at the bottom of the day's range.
2. What's new
On September 28 at 08:30 ET MongoDB filed an 8-K under Items 5.02 and 7.01: chief executive CJ Desai resigned effective immediately to take a senior role at Meta Platforms, and Dev Ittycheria, chief executive from September 2014 to.
3. What that does to the state
Monday's filing does not replace the September 1 quarter, and it changes no number in the guide.
300 similar days · 179 stocks · 244 sessions · 1h band
| Vs the market, in points | Low | Middle | High | Share up |
|---|
| 1 session | -4.5 | -0.1 | +4.0 | 49% |
| 5 sessions | -11.4 | -0.8 | +9.8 | 43% |
| 10 sessions | -16.3 | -0.4 | +16.5 | 49% |
The band is the prior close's neighborhood — what followed similar states as of the cutoff.
4. Same state, or a new one
Left yesterday's range
Session 1 vs the market: -17.7. Prior-state 1-session range: -4.5 / -0.1 / +4.0.
An investor-day target on Tuesday below the reaffirmed fiscal 2027 guide, a naming of a permanent chief executive, or a Tuesday close outside the 1-session band of Monday's state once the memory has it, would make Monday's filing the needle.
Session 1: -17.7 vs band -4.5/-0.1/+4.0, left yesterday's range. Session 5: 2026-10-02. Scorecard
Friday's close was $410.44, down 2.6% from a $421.40 prior close, on 1.35 million shares, 0.71 times the recent norm, and $555 million of stock. The close sat at the bottom of the day's range, 13.2% under the 52-week high of $473.10 from August 14, and 62.2% above the close of 120 sessions ago. That was the completed state going into Monday.
Monday's filing came at 08:30 ET. Chirantan Desai resigned as president and chief executive, effective September 28, to pursue a senior role at Meta Platforms. The board named Dev Ittycheria, who held the job from September 2014 to November 2025, interim president and chief executive, effective the same day, and retained a search firm. The release reaffirms the third-quarter and fiscal 2027 guidance given on September 1 and keeps the investor day on Tuesday, September 29, 11:00 to 15:15 ET. The 8-K says the departure was not due to any disagreement with the company.
The last number is still September 1. Second-quarter revenue was $771.8 million, up 30%, Atlas grew about 29%, non-GAAP net income was $1.90 a share, and free cash flow was $137.6 million. The fiscal 2027 guide is revenue of $2.99 billion to $3.03 billion and non-GAAP earnings of $6.39 to $6.58 a share. The stock fell 17.2% the next session, to $375.40, then to $356.00 by September 8, then rose 20.3% in eleven sessions to $428.36 on September 23, ahead of the investor day. Monday's tape, from the exchange feed and not yet in the memory: an open of $311.75, 24.0% under Friday's close, a low of $300.00, a high of $344.14, and a last print near the bell of $335.55. The memory's band is on Friday's state; Monday's own state arrives with tonight's ingest.
Other reading, tape, and sources
The other reading
The guide is reaffirmed, the interim chief executive ran the company for eleven years, and the investor day puts long-term targets on the table on Tuesday, so a 24% opening gap on a personnel filing with no number in it is a leadership repricing, not a demand print. The other reading is the one the tape took: a chief executive leaving ten months into the job, for Meta, the day before an investor day, is the fact the run from $356.00 to $428.36 had not priced.
What would change this
An investor-day target on Tuesday below the reaffirmed fiscal 2027 guide, a naming of a permanent chief executive, or a Tuesday close outside the 1-session band of Monday's state once the memory has it, would make Monday's filing the needle. A reaffirmed guide restated on Tuesday, with the stock inside Monday's band, would not.
The tape
Friday's close was $410.44, down 2.6% from a $421.40 prior close, 13.2% under the August 14 high of $473.10, 62.2% above the close of 120 sessions ago, and 19.1% above its 200-day. Volume was 0.71 times the recent norm and $555 million traded. The close sat at the bottom of the day's range. The memory files the state as a 120-day uptrend, above its 200-day, off the 52-week high, with overhead supply, quiet volume, a weak close, and some peers moving.
What was filed
On September 28 at 08:30 ET MongoDB filed an 8-K under Items 5.02 and 7.01: chief executive CJ Desai resigned effective immediately to take a senior role at Meta Platforms, and Dev Ittycheria, chief executive from September 2014 to November 2025 and still a director, became interim president and chief executive. His October 29, 2025 advisory agreement stays in force. The board retained an executive search firm. The company reaffirmed the third-quarter guide of $756 million to $761 million of revenue and $1.57 to $1.61 a share, and the fiscal 2027 guide of $2.99 billion to $3.03 billion and $6.39 to $6.58 a share, both from September 1. The investor day proceeds Tuesday, September 29, 11:00 to 15:15 ET at Nasdaq MarketSite.
The numbers around the move
Monday's filing does not replace the September 1 quarter, and it changes no number in the guide. The 5-session excess band on Friday's state is -11.4 / -0.8 / +9.8 across 300 analogs, 2.3 times the base width for this kind of session. Monday's open, 24.0% under Friday's close, is outside every band the memory holds for Friday's state, so Monday is a new state, not a test of the old one. Its band is read after tonight's ingest.
What the stock did
Monday's session is the reaction to the 08:30 filing. From the exchange feed: an open of $311.75, a low of $300.00, a high of $344.14, and a last print of $335.55 before the bell, 18.2% under Friday's close. The completed close is not in the memory yet. Tuesday's investor day is the next print, and Tuesday's close is the first test of Monday's state.
The comparison
Five-session excess -11.4 / -0.8 / +9.8 across 300 analogs on the 1-hour scale, with the up-share at 43%. One session -4.5 / -0.1 / +4.0. Ten sessions -16.3 / -0.4 / +16.5. The band is 2.3 times the base width. These describe Friday's state, before the filing. 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 28 8-K and its exhibit 99.1, accepted at 08:30:44 ET. The quarter and the reaffirmed guide are the September 1 exhibit 99.1. Monday's open, low, high and last print are the IEX feed read at 15:58 ET, before the closing auction; the completed session enters the memory with tonight's ingest. The September 2 to September 23 path is from stored daily closes; the memory holds no September 1 session for MDB, so the report-day close is not quoted.
- September 25 completed-session state packet for MDB · Available Sep 25, 2026 · 9:00 pm ET
- MongoDB 8-K, September 28, 2026: Items 5.02 and 7.01, chief executive transition · Available Sep 28, 2026 · 8:30 am ET
- MongoDB exhibit 99.1, September 28, 2026: CEO transition, guidance reaffirmed, investor day · Available Sep 28, 2026 · 8:30 am ET
- MongoDB exhibit 99.1, September 1, 2026: fiscal second-quarter 2027 results and guidance · Available Sep 1, 2026 · 4:07 pm ET
- IEX daily bar for MDB, September 28, 2026, via Alpaca Market Data, read at 15:58 ET · Available Sep 28, 2026 · 3:58 pm ET