Starling Murmuration
Stocks flocking together by how they move
The COVID crash · Mon, Mar 16, 2020
One flock
198 of 200 fell · median -12.5%
One flock on Monday, March 16, 2020
One flock: over the past month, nearly every stock rose and fell as one.
198 of the 200 birds fell that session, by a median -12.5%.
MRNA flew furthest from the flock: +24.4%.
The COVID crash, Feb–May 2020. The fastest bear market in history. On March 16 nearly every bird fell at once, and the flock pulled into a tight ball over the sea.
Split-adjusted daily closes for the 200 largest US-listed companies by today’s market cap that traded through each episode; companies based abroad are left out. Built Friday, October 9, 2026. Not financial advice.
How to read the flock
Each bird is one of today’s 200 largest US companies that traded through the episode. Its place in the flock comes from how its price moved over the past month: stocks that traded alike fly side by side.
When stocks rise and fall together, the flock pulls into one tight shape. On a stock-picker’s day, when each stock follows its own news, it spreads across the sky.
Each session, a bird that rose climbs and a bird that fell dives, so a crash is a mass dive. The whole flock sinks as the market falls and climbs as it recovers.
The color button paints the birds by industry: in a rotation, whole industries peel away together.
The five levels, from scattered to one flock, grade the average correlation of the birds’ daily moves over the past month. Market State tracks how tightly stocks move together every day.
It shows history. It is not a forecast.
Twelve episodes
Stretches of market history where the flock tightened, scattered, or both. Each opens on its most telling session.
- Liberation DayMar–May 2025
New tariffs on April 2 sent stocks tumbling together. On April 9 a 90-day pause sent almost every bird soaring at once.
Opens on Wednesday, April 9, 2025
- The yen carry unwindJun–Sep 2024
A scattered summer, with money rotating out of the giants into everything else, ended in the August 5 sell-off.
Opens on Monday, August 5, 2024
- The 2022 bear marketApr–Jul 2022
Inflation and rate hikes pressed on everything at once. The flock tightened through the spring and into June.
Opens on Monday, June 13, 2022
- The meme-stock squeezeJan–Mar 2021
GameStop ran wild, but the big birds barely noticed: the flock stayed loose, with one sharp dive on January 27 as hedge funds sold.
Opens on Wednesday, January 27, 2021
- Vaccine MondayOct–Dec 2020
On November 9 Pfizer’s vaccine results sent banks and energy soaring while stay-at-home tech fell. Color the birds by industry to watch them part.
Opens on Monday, November 9, 2020
- The COVID crashFeb–May 2020
The fastest bear market in history. On March 16 nearly every bird fell at once, and the flock pulled into a tight ball over the sea.
Opens on Monday, March 16, 2020
- The Christmas Eve sell-offOct 2018–Jan 2019
A rate-hike scare slid into the worst Christmas Eve session on record, and then a rebound on December 26.
Opens on Monday, December 24, 2018
- VolmageddonJan–Apr 2018
A calm, scattered January ended on February 5, when volatility spiked and the flock snapped together.
Opens on Monday, February 5, 2018
- The quiet yearJun–Oct 2017
One of the calmest markets on record. Each stock followed its own news, and by October the flock was spread across the sky.
Opens on Thursday, October 12, 2017
- The US downgradeJul–Oct 2011
S&P cut America’s credit rating on August 5. The next Monday almost every bird dived, and the flock flew as one for weeks.
Opens on Monday, August 8, 2011
- The Flash CrashApr–Jul 2010
On May 6 the Dow dropped nearly 1,000 points in minutes. A scattered spring flock tightened within days and stayed tight all summer.
Opens on Thursday, May 6, 2010
- The Lehman crashAug–Dec 2008
Lehman Brothers failed on September 15. By October the flock had pulled into one shape, and it stayed that way into December.
Opens on Thursday, October 9, 2008