Week of September 28: MU Led Every Session, SPX GEX Swung From −37.95 to +19.74
Five Daily Market Recap sessions and three Rank reads. MU carried the most option premium every day, $1.6B to $3.5B. SPX index GEX stayed Negative for four sessions, reached −$37.95B on Thursday, and printed +$19.74B on Friday. SPY closed on its $764 0DTE top Thursday and between $769 and $770 Friday.
This is a weekly readout of Daily Market Recap and Rank structure for September 28 – October 2, 2026. It is not a trade.
The week had two threads. MU carried the most single-name option premium in all five sessions. SPX index GEX stayed Negative for four sessions, deepened to −$37.95B on Thursday, then printed +$19.74B on Friday, with every index row Positive. SPY finished the week $1.80 under the prior Friday's close.
Daily editions: September 28 · September 29 · September 30 · October 1 · October 2.
Five session closes versus T+1 structure, with recap tape and index GEX by session. GEX is prior-close. Price bars are the session. Not a forecast.
Readers with access can lock the recap to each date: 9/28 · 9/29 · 9/30 · 10/1 · 10/2. Sign-in and an eligible trial or subscription may be required.
What the week printed
| Session | Single-name premium | Tone | SPX index GEX | SPY close | Rank 0DTE close vs structure |
|---|---|---|---|---|---|
| Mon Sep 28 | $14.8B, 64% calls | Leaned bearish 23 / 25 | −14.54 | 766.60 | No Rank structure for this session |
| Tue Sep 29 | $14.4B, 63% calls | Leaned bearish 24 / 26 | −14.56 | 765.60 | No Rank structure for this session |
| Wed Sep 30 | $14.0B, 67% calls | Leaned bullish 24 / 22 | −17.39 | 764.20 | 0DTE horizon empty; all-expiration Negative, close $3.97 under the flip |
| Thu Oct 1 | $17.1B, 60% calls | Balanced 23 / 23 | −37.95 | 764.00 | Negative; close on the $764 0DTE top (74.4% of 0DTE gross) |
| Fri Oct 2 | $16.8B, 69% calls | Balanced 24 / 23 | +19.74 | 769.60 | Positive; close between the $769 put wall and $770 top |
The five recap tapes add up to $77.1B of single-name premium. SPY closed 771.40 the Friday before and 769.60 this Friday, after four lower closes in a row. SPX index GEX is the recap's T+1 snapshot for each session; SPY OHLC and the 0DTE walls are Rank's.
MU: the heaviest name every session
| Session | MU premium | Net bias | Last | Avg IV (traded) | Largest listed print |
|---|---|---|---|---|---|
| Sep 28 | $1.6B | Bearish | $1,054 | 79% | 720C / 740C Oct-16, $9M each, Neutral |
| Sep 29 | $1.7B | Bearish | $1,065 | 93% | 1,050C Nov-20, $78M, Bearish |
| Sep 30 | $2.3B | Bullish | $1,069 | 105% | 1,050C Nov-20, $10M, Bullish |
| Oct 1 | $3.5B | Bullish | $1,098 | 72% | 1,200C Dec-18, $61M, Neutral |
| Oct 2 | $1.9B | Bearish | $1,075 | 75% | 1,070P Jan-27, $11M, Bearish |
The five MU readings add up to $11.0B, about 14% of the week's single-name tape. Premium peaked Thursday at $3.5B. Average IV on traded MU contracts rose to 105% on Wednesday and was 72% the next day. The net bias tag went Bearish, Bearish, Bullish, Bullish, Bearish. Several sessions printed MU $0.1B lower in the bottom line and glance than in the leaders table; the table above uses the leaders figure, and each daily edition quotes both.
Index GEX: four Negative sessions, then every row Positive
| Index | Sep 28 | Sep 29 | Sep 30 | Oct 1 | Oct 2 |
|---|---|---|---|---|---|
| SPX | −14.54 | −14.56 | −17.39 | −37.95 | +19.74 |
| SPY | −3.33 | −1.01 | −1.44 | −11.95 | +7.77 |
| QQQ | −2 | −3.2 | +1.6 | −6.2 | +7.5 |
| NDX | +0.26 | +0.69 | +0.69 | +6.51 | +8.3 |
| IWM | −0.94 | −0.76 | −0.5 | −0.32 | +0.18 |
| DIA | −0.01 | −0.01 | −0.06 | −0.03 | +0.14 |
Net GEX in $B, from each session's Daily Market Recap (T+1 snapshot). The prior Friday, September 25, had SPX at +$80.06B. NDX was the only index Positive in all five sessions. Friday's table is the first all-Positive index table in this digest's daily editions. The October 1 column is the settled snapshot; an early run printed different values, as that edition's revision note records. These are five snapshots, not a measured path between them, and Negative or Positive GEX is modeled structure, not observed dealer inventory.
Thursday and Friday on Rank
Thursday's 0DTE books were Negative and both closes sat on the T+1 top: SPY 764.00 on the $764 put wall / 0DTE top, which held 74.4% of the 0DTE book's selected-range gross, and SPXW 7,666.40, 1.40 over the 7,665 top. The October 1 edition has the annotated shots.
Friday's books were Positive, and both closes sat just under the top strike.
Test app, session 2026-10-02, horizon Today · 0DTE. Positive gamma, 0DTE 21.6% of all-expiry gross. Top $770 (33.4%), put wall $769, flip $767.33, close 769.60. Captured October 3, 2026.
Same session, SPXW, horizon Today · 0DTE. Positive gamma, 0DTE 28.2% of all-expiry gross. Top 7,725 (59.0%), put wall 7,720, flip 7,719.04, close 7,722.70. Captured in the test app on October 3, 2026.
Same strikes, different regime: Thursday's close sat on a top inside a Negative book; Friday's sat just under a top inside a Positive book. That is the same shape as September 9 and September 25 respectively. It describes two sessions against T+1 structure; it is not a pin forecast.
What the week cannot show
- Monday and Tuesday on Rank. The Symbols GEX page returns no research data for September 28 and 29, so there is no wall reading for those sessions.
- Wednesday's same-day map. September 30's structure was built at 5:29 AM ET on October 1, after that session's expiries, so Today · 0DTE reads 0.0%. Only the all-expiration book is available.
- Some daily bars. Rank's September 28 and 29 bars repeat the same open, high, and low on both SPY and SPXW, and the October 2 SPXW bar's range is far narrower than SPY's. This week quotes closes for those bars and full OHLC only where SPY and SPXW agree.
- One-word movers. The recap's Step 7 key result can name the top gainer on one run and the top loser on another; the daily editions quote the bottom-line mover and say which run.
What this week is evidence of
| Question | TradingFlow, Sep 28 – Oct 2 | Clock |
|---|---|---|
| Which name carried the most option premium? | MU every session; $11.0B across five, peak $3.5B Thursday | Session leaders |
| How large was the single-name tape? | $14.0B–$17.1B a session; $77.1B across five | Session premium |
| Did the tape lean? | Bearish, bearish, bullish, then balanced twice; no gap above two points | Session sentiment |
| What did SPX index GEX do? | −14.54 → −14.56 → −17.39 → −37.95 → +19.74 | T+1 snapshots |
| Where did SPY close against same-day structure? | Thursday on the $764 top (Negative); Friday between $769 and $770 (Positive) | T+1 0DTE GEX + session OHLC |
| Where did SPY finish the week? | 769.60, $1.80 under the prior Friday's 771.40 | Session closes |
One week is not a trend. Proxies (intraday_pct, simplified GEX) are descriptive estimates, not price forecasts.
Reproduce the week
- Open Daily Market Recap and lock each session from Sep 28 to Oct 2, 2026. Record total premium, tone, the leaders table top row, and the Step 6 index GEX table.
- Confirm MU at the top of Step 2 in all five runs, and note the bottom-line / leaders premium difference where it appears.
- Open SPY Gamma Exposure for Oct 1 and Oct 2 → horizon Today · 0DTE. Record environment, walls, flip, and the daily close. Repeat for SPXW. Sign-in and a paid entitlement may be required.
- Open Sep 30 and confirm the 0DTE horizon reads 0.0%.
- Stop before "therefore buy MU" or "therefore next week stays positive GEX."
TradingFlow App Home → Cookbooks → Daily Market Recap for the session lock → Symbols → GEX for walls and flip.
Related reading
- October 2 Recap: Balanced Tape, MU $1.9B, SPX GEX Positive
- October 1 Recap: Balanced Tape, MU $3.5B, SPX GEX Negative
- Week of September 1: The Bounce Ran 761 to 7750, Then Sat on 770 / 7720
- Daily Market Recap: read a full options session in Cookbooks
- Negative GEX is session risk, not a trade
- Call/put walls on a pin day
Learn more
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October 1 Recap: Balanced Tape, MU $3.5B, SPX GEX Negative
Daily Market Recap on the completed October 1 session printed $17.1B of single-name premium, 60% in calls, with tone balanced at 23% bullish vs 23% bearish. MU led a fifth session running at $3.5B (Bullish). SPX GEX was Negative at −$37.95B, with SPY and QQQ Negative too, and Rank showed SPY closing on its $764 0DTE top.
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September 25 Recap: Balanced Tape, MU $1.7B, SPX GEX Positive
Daily Market Recap on the completed September 25 session printed $15.6B of single-name premium, 70% in calls, with tone balanced at 22% bullish vs 23% bearish. MU led at $1.7B (Mixed). SPX GEX was Positive at +$80.06B, and Rank showed SPY and SPXW closing between their 0DTE put wall and 0DTE top.