The market has a headline and a story underneath
Imagine two markets on the same day. In one, nearly every stock joins the climb. In the other, a few large companies pull the index higher while much of the list slips lower. The headline can look identical. The market underneath it is not.
Market breadth is a way to look underneath that headline. Instead of asking only what the index did, it asks how many stocks helped create the move. tradingtwohundred uses the share of S&P 500 members above their 200-day moving average as a consistent participation reading. It does not predict tomorrow. It shows how much company the move has today.
1. Participation
Start with what breadth measures and why the number can tell a different story from the index.
2. Context
Then learn how to read the dashboard across history, sectors, distribution, and crosses.
3. Perspective
Finally, learn what the signals cannot tell you before using them as evidence in your own research.
That is the purpose of this section. The guides explain the language, the market tools show the latest evidence, and the weekly digest connects the pieces in plain English. If you want the exact definitions behind the data, read the data and methodology notes as well.
All Guides
13 guides · about 73 min in total
New to market breadth?
Start with the first three guides. Begin with the story behind the 200-day line, learn what market breadth measures, and then use the dashboard to see the ideas with the latest data.
- 1
Start here
3 guides · 17 min
01Start hereThe Line Everyone Watches
On March 23, 2020, the S&P 500 hit its pandemic low at 2,237. In the weeks that followed, something remarkable happened: despite a global health crisis, unprecedented unemployment, and economic chaos, the market began to climb. By early June, the S&P had rallied 40% from that low.
6 min readRead02Start hereMarket Breadth, Explained
The S&P 500 can look healthy even when many of its individual stocks are struggling. Market breadth helps you see how widely a move is being shared beneath the index.
6 min readRead03Start hereThe Dashboard, Decoded
A quick tour of the headline breadth number, sector breakdown, moving-average charts, cross scanners, and the questions each tool can help you answer.
5 min readRead - 2
Beginner
6 guides · 30 min
04BeginnerThe Memory of the Market
In 1906, the British scientist Francis Galton visited a livestock fair in Plymouth. He was seventy-four years old, increasingly preoccupied with questions of collective intelligence, and what he found that afternoon would change how we think about crowds forever.
5 min readRead05BeginnerWhen the Index and Its Stocks Disagree
An index is an average. Breadth asks how many individual stocks are helping create that average, which can reveal a rally that is broadening, narrowing, or losing support.
5 min readRead06BeginnerGolden Cross or Death Cross?
These names sound dramatic, but the underlying idea is simple: compare a shorter trend with a longer one and treat the result as context, not a verdict.
5 min readRead07BeginnerWhat These Signals Can and Cannot Tell You
Moving averages and breadth are useful summaries of market behavior. They are not predictions, guarantees, or substitutes for a plan that fits your own risk.
5 min readRead08BeginnerThe Moment of Recognition
On March 9, 2009, the S&P 500 closed at 676.53. It was the lowest point of the financial crisis, though nobody knew it at the time. The headlines that week were apocalyptic.
5 min readRead09BeginnerThe Warning You Ignore at Your Peril
On December 21, 2007, the S&P 500's 50-day moving average crossed below its 200-day moving average. Most investors didn't notice.
5 min readRead - 3
Intermediate
2 guides · 12 min
10IntermediateThree Stories About Fear and Greed
Markets don't repeat, but they rhyme. The details change—the catalyst, the timing, the magnitude—but the underlying dynamics remain remarkably consistent.
6 min readRead11IntermediateThe Art of Doing Less
In 1985, a little-known fund manager named Peter Lynch published a book called One Up on Wall Street. In it, he described what he called the "Peter Principle" of investing.
6 min readRead - 4
Advanced
2 guides · 14 min
12AdvancedThe Weather Map
For most of 2022, a strange and unwelcome thing kept happening to millions of retirement accounts. Stocks fell. That was expected. But bonds fell too. At the same time. By a lot.
7 min readRead13AdvancedThe Season Before Spring
In the mountains of Kyushu, Japan, farmers plant moso bamboo and then wait. They water it every day. They fertilize the soil. They tend to it through spring rain and summer heat and the dry cold of winter. And for four years, sometimes five, nothing visible happens.
7 min readRead
Why the 200-Day MA?
The 200-day moving average is a widely followed reference line built from roughly one year of trading sessions. It can make the longer trend easier to see and gives the breadth reading a consistent threshold. These guides explain how to use it as context, not as a standalone answer.
Disclaimer: Data is provided for informational purposes only and is not intended as investment advice. Always do your own research before making investment decisions. We are not responsible for any losses incurred from using this information.
