Chapter XVII opens with a friend’s story attributing Livingston’s sale to a black cat and a mysterious hunch. Livingston distinguishes that legend from his own account of observations and warning signs. Even his explanation of intuition remains a personal interpretation rather than a measured forecasting record.
When reviewing a decision, reconstruct the information available beforehand. Avoid replacing analysis with a memorable anecdote, whether it celebrates genius or blames bad luck. The question for learning is which observations were useful, what alternatives existed, and whether the same method can be assessed across multiple decisions.
Worked example
A diary records three concerns before a sale. A later retelling mentions only the one that appears prophetic. Compare the original entry with the retelling to see what hindsight has removed.
Case connection
The Flash Crash investigation used trading records and liquidity evidence to reconstruct a sequence that a price chart alone could not explain. That is a practical contrast to attributing a complex event to a single dramatic story.
The Flash Crash: price and liquidity
Source-grounded facts
E-mini futures and SPY fell about 5% within five minutes, then recovered over the next ten. Investigators examined order-book liquidity.
Context
On 6 May 2010, US equity and futures markets experienced a sharp, short-lived disruption. Investigators needed more than closing prices to reconstruct the episode.
Outcome
The price recovery did not erase the disruption. The investigation used trading records and liquidity data to distinguish the sequence of events from stories based only on a chart.
Further analysis
A market can have a closing price and still break intraday
On 6 May 2010, US equity and futures markets suffered a sharp, brief disruption. The reported account describes E-mini S&P 500 futures and SPY falling about 5% within five minutes and recovering over roughly the next ten. Some individual securities traded at extreme prices during the episode. A chart containing only daily closes could hide much of that experience. The investor who needed to trade during the disruption faced a different problem from the reader studying only the end-of-day result.
Liquidity is not the same thing as a last traded price
A last price records a completed transaction. Market depth describes quantities available for possible new transactions at different prices. The two can tell very different stories when orders are withdrawn, filled quickly, or submitted under stress. The SEC staff analysis examined order books and noted a dramatic decline in futures buying depth before related equity liquidity problems. That is why an explanation needs a sequence of trading conditions, not just the shape of a line joining a few prices.
Why recovery does not erase execution risk
Suppose a holder must sell during a short disruption because of a financing obligation or an urgent liquidity need. A recovery several minutes later cannot automatically repair the transaction already executed. This is a general mechanism, not a claim that all participants sold at the worst point. Market orders and limit orders also address different priorities: seeking execution is not the same as specifying a minimum acceptable price. Either can leave a risk unresolved when the market is changing quickly.
How to avoid an overconfident explanation
It is tempting to assign a complex event to one dramatic trade or one type of participant. The staff account instead motivates studying interactions between trading activity, available depth, and the timing of the disturbance across markets. A five-minute fall does not by itself reveal every causal contribution. A careful reader distinguishes what the cited analysis reports from a broader theory about electronic markets. The event does not establish that every fast move has the same cause, or that every apparent recovery is easy to trade.
A practical lesson without a timing prediction
Ask how the planned transaction changes if only a fraction of normal depth is available. Examine position size relative to liquidity, the order’s actual terms, and any obligation that could force action at a poor moment. These questions concern the resilience of a plan, not predicting the next flash crash. The learning-lab price paths can illustrate why identical ending values conceal different journeys, but those invented paths are not a reconstruction of the 6 May tape. We do not draw a fabricated historical stock-price series for this case.
Common misconception
“The market recovered, so nobody faced a serious risk.” Closing or later prices do not describe every transaction during the event. Execution timing and constraints change the outcome.
- Around 2:40 p.m., E-mini S&P 500 futures and SPY fell roughly 5% in five minutes, then recovered over the next ten.
- During the recovery, some individual stocks and ETFs traded at extremely low prices before rebounding.
- Staff examined full order books and found that futures buying depth had fallen dramatically; equity liquidity problems followed.
Try it
Reconstruct an investment decision from dated evidence. Mark each fact as known at the time or learned afterward.