Published Sep 28, 2026, 4:34 PM ET
Today's move, what drove it, and what the available information cannot explain.
Capitalisation weighted, so a move in the largest companies moves it more than a move in the smallest.
Every Nasdaq listing, weighted by capitalisation and heavy in technology.
Thirty names weighted by price rather than by capitalisation, so it can disagree with the S&P for arithmetic reasons alone.
Small capitalisation names. Read against the S&P, it is the size half of how broad a day was.
The same five hundred companies weighted equally, so the largest names count no more than the smallest. Read against the cap-weighted index, the gap is how much of the day belonged to the biggest companies.
The two moved together, so the session was not a story about the largest companies.
38%
3 of 8 tracked indices above their 50-day average
Counted over ^GSPC, ^IXIC, ^DJI, ^RUT, ^FTSE, ^N225, ^GDAXI, 000001.SS. This is a reading across whole market indices, not a count of the companies inside any one of them.
CNN's own index, stored at the close. Context for whether sentiment confirms the tape or contradicts it.
Expected thirty day volatility from S&P 500 options. Rising with the index is the contradiction worth seeing.
CEO Desai's departure to a Meta enterprise platform role announced same day as the sharp share drop.
News event dated 2026-09-28, MarketWatch Top Stories: MongoDB CEO Desai departs for Meta enterprise platform role
Moved 18.5%, at or above the 3% floor for this strip
737 Max 10 certification delayed by a software issue, disclosed the same day shares fell nearly 7%.
News event dated 2026-09-28, CNBC Top News: Boeing 737 Max 10 certification delayed by software issue
Moved 6.9%, at or above the 3% floor for this strip
The evidence read for this company over the 7 days before the session was its own SEC filings, its stored corporate actions, the headline feed collected for its ticker and the clustered news events this system collects every two hours across every category. Rows naming this company were read inside that window and none of them was resolved to this session's move.
Moved 5.7%, at or above the 3% floor for this strip
The evidence read for this company over the 7 days before the session was its own SEC filings, its stored corporate actions, the headline feed collected for its ticker and the clustered news events this system collects every two hours across every category. Rows naming this company were read inside that window and none of them was resolved to this session's move.
Moved 4.8%, at or above the 3% floor for this strip
The evidence read for this company over the 7 days before the session was its own SEC filings, its stored corporate actions, the headline feed collected for its ticker and the clustered news events this system collects every two hours across every category. None of them holds a row for this company inside that window.
Moved 4.4%, at or above the 3% floor for this strip
The evidence read for this company over the 7 days before the session was its own SEC filings, its stored corporate actions, the headline feed collected for its ticker and the clustered news events this system collects every two hours across every category. Rows naming this company were read inside that window and none of them was resolved to this session's move.
Moved 4.3%, at or above the 3% floor for this strip
The evidence read for this company over the 7 days before the session was its own SEC filings, its stored corporate actions, the headline feed collected for its ticker and the clustered news events this system collects every two hours across every category. None of them holds a row for this company inside that window.
Moved 4.1%, at or above the 3% floor for this strip
Built in code from the movers whose evidence did not resolve, so no written summary can shorten this list.
The S&P 500 fell 0.77% while 3 of 8 tracked indices sat above their own 50-day average, up from 2 of 8 last session, so the decline came alongside a small rise in participation rather than a further narrowing.
Nasdaq fell 0.92%, more than the S&P 500's 0.77%, Dow's 0.67% and Russell 2000's 0.69%, showing the decline was broad across large caps, mega caps and small caps together.
Sector performance split, with Health Care up 0.33% and Consumer Staples up 0.27% against Communication Services down 1.58% and Consumer Discretionary down 1.41%, a much wider spread than the prior session's divide.
VIX rose 8.07% while Fear and Greed fell 8.11%, both readings pointing toward increased fear together, matching the two moving in the same direction as before but now in the opposite sense.
One session, from the stored closes of the eleven sector ETFs. Each bar is scaled against the widest move of the day, so the shape is the spread and not an absolute size.