A photograph looking straight down the long central aisle of a vast old covered market hall in late afternoon, iron ribs and high dirty skylights overhead. Every stall on both sides is fully stocked and abandoned mid-transaction — produce stacked in crates, sacks of flour heaped by a post, a chair tipped over, an apron left hanging from a stall frame — and not one vendor or customer anywhere in the aisle. The overhead lamps are flickering on for the evening, washing the emptiness in a cold electric violet. On the bare counter of the nearest stall, alone in a pool of the violet light, lies a single small copper coin. Far away at the end of the aisle, tiny with distance, the first figures are just returning. In the near ground, alone, seen from behind, stands a man in full clown makeup and a grey suit a half size too big — tidy lavender side-parted hair — perfectly still, facing down the long empty aisle, his hands clasped behind his back holding a small brown paper bag. There is nobody near him.

The air pocket

S&P 500 1,128.15 · −37.72 · −3.24%

For thirty-six minutes the market discovered what it is when nobody bids. Then the bids came back, as algorithmically as they left.

The photograph Retail at the Empty Market

The day's protagonist

The bid — no symbol.

Move: Withdrawn, everywhere, at once — Accenture traded for one cent

It was already a bad day: Greece was burning on every screen. At 2:32 a large automated sell program began working through the E-mini futures, and the high-frequency firms that usually stood on the other side stepped away together. What followed was not selling but absence — Accenture, a company with twenty billion in revenue, printed at a penny; other names printed at hundred-thousand-dollar stub quotes, because those were the only orders left in the book. Thirty-six minutes later the bids returned and the market closed at merely terrible. More than twenty thousand trades were cancelled as clearly erroneous. The scar is structural: per-stock circuit breakers exist because of this half hour.

The deeper account

The mechanism, per the regulators' joint report: one large automated E-mini sell order, working by volume percentage, met a market that had stopped absorbing — liquidity begat selling begat less liquidity.

In 2015 a trader named Navinder Sarao was arrested in his parents' London bedroom, charged with spoofing the same futures that afternoon. The market's strangest half hour has multiple authors and no satisfying one.

The half hour built this wing: nearly every page that follows — Knight, the fake tweet, the limit-down opens — happens inside market structure this day exposed.

The close was an ordinary bad day, and the crash itself was over before most people found the television remote. The record keeps the strangeness in the almanac instead.

Wing 4 opens here. The Strange Decade: ten days in which the machines, the platforms, and the overnight became the market's main characters.

The artifact

The inspector's stall census — taken during the half hour, filed as if it couldn't have happened

The census records an absence, which is the hardest thing a record can hold: every stall stocked, not one attended, and the only prices left in the hall a penny and a hundred-thousand-dollar stone — the stub quotes that were the book scraped bare. The stamp is the exchanges' own word for what they did to twenty thousand of the afternoon's sales. The fine print keeps the distinction that built this wing: the sales were erased, and the half hour was not.

Read the stall census

Printed text is shown plain; handwritten entries are shown in script.

MARKET INSPECTOR · THURSDAY, MAY 6 · STALL CENSUS · 2:32 – 3:08

stalls — all. stocked, mid-transaction.
attended — none.
on a counter — one coin. one cent. against goods worth twenty billion.
on a scale — a stone, priced one hundred thousand.
3:08 — the vendors returned, as one, the way they left.
ERASED: 20,000+ sales, as clearly erroneous.
BUSTED SALES MORE THAN 60% FROM REALITY WERE ERASED · THE HALF HOUR WAS REAL

At 2:32 p.m. a large automated sell program met a market that had stopped absorbing; the high-frequency bids withdrew together. Accenture — twenty billion dollars in revenue — printed at one cent; Sotheby's printed at $100,000: stub quotes, the only orders left in the book. The S&P 500 touched 1,065.79 and closed down 3.24 percent at 1,128.15; the Dow was down 998.5 points intraday. More than 20,000 trades were cancelled as clearly erroneous, and per-stock circuit breakers exist because of this half hour.

The ledger — what actually happened

Measure	Close	Change	Marginalia
S&P 500	1,128.15	−37.72 · −3.24%	the close; the day's true floor was 1,065.79, touched for moments
Dow Jones	10,520.32	−347.80 · −3.20%	down 998.5 points intraday — the largest intraday point drop to that day, noted here unsealed
Accenture	$0.01		a real company at a penny; Sotheby's printed at a hundred thousand — stub quotes, the book scraped bare
Busted trades	20,000+		cancelled as clearly erroneous — executions more than 60% from reality
The backdrop	Athens		Greek debt riots on every screen; the day was falling before it fell

Sources

Wikipedia — 2010 flash crash — https://en.wikipedia.org/wiki/2010_flash_crash
CNBC — The lasting impact of the 2010 flash crash — https://www.cnbc.com/2014/05/06/the-lasting-impact-of-the-2010-flash-crash.html
Corporate Finance Institute — 2010 Flash Crash overview — https://corporatefinanceinstitute.com/resources/equities/2010-flash-crash/
CFTC/SEC joint report, September 2010 — Findings Regarding the Market Events of May 6, 2010