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StockMarketAgent
Market outlook · Section 2

Market breadth

Bear-side framing first. Breadth has narrowed materially: five mega-caps account for 71% of YTD index return. A cap-weighted index riding on a handful of names is fragile; one built on broad participation is durable. The historical percentile column is the contextual sanity check — an absolute reading without history is decoration.

Signal: narrowing
UniverseS&P 500
As of2026-05-09
CadenceDaily close
Composite

Breadth health

A single 0–100 score blending trend participation, advance/decline momentum and new-high expansion into one verdict on how broad the market really is. The lower the score, the more the index is carried by a narrowing cohort.

Composite breadth health

How broad is the rally

39
Weak
▼ 16 pts vs last month (55)
Deteriorating025
Weak2545
Mixed4560
Constructive6078
Broad78100
Verdict bands run Deteriorating · Weak · Mixed · Constructive · Broad. A reading below the Mixed band means the tape is leaning on too few names.
Trend participation

How many names hold their trend

The share of constituents trading above their 50-day and 200-day moving averages — the cleanest read on whether the advance is broad or carried by a narrow leadership cohort.

Trend participation

% of S&P 500 above moving average

41%
Above 50d SMA
47%
Above 200d SMA
A reading above the 50% waterline means more than half the index holds its trend. The faster 50-day line leads; the slower 200-day line is the structural backdrop.
The components

What’s beneath the index

Six participation measures, each with its current reading, month-over-month direction, and ten-year historical percentile. The percentile is the discipline: it stops a single absolute reading from being mistaken for a signal.

IndicatorValueΔ MoM10y %ile
% S&P 500 above 200d MA
47.0%
P28
% S&P 500 above 50d MA
41.0%
P22
% making new 52-week highs
4.6%
P31
NYSE adv/dec line slope (20d)
-0.34
P18
Cap-weight − equal-weight YTD return spread
9.2%
P92
Top 5 mega-caps share of YTD index return
71.0%
P96
The read

What breadth is signalling

The headline number is doing more concealing than describing. The cap-weight minus equal-weight spread sits in the top decile of its history and the top-five share of index return is near a record, while well under half of constituents hold their 50-day average. That combination — a narrow few carrying a wide index — is the defining feature of this tape.

Narrowing breadth is a leading-but-noisy indicator: it leads drawdowns more often than not, but the historical lead time has ranged from six weeks to nine months. Pair this surface with the regime scorecard and the scenarios page — one signal in isolation is not a portfolio decision.

History

Breadth through the cycle

Percent of the S&P 500 above its 200-day moving average, monthly. The dashed line marks the 50% waterline that separates broad strength from broad weakness — readings below it are the structural-trend warning.

36-month history

% of S&P 500 above 200-day MA

% above 200-day MA50% waterline
405060708050% waterline2023202420252026
Monthly close, 2023-06 – 2026-05. The latest reading sits below the 50% waterline, consistent with the narrowing signal above.
Keep reading

The rest of the outlook

Breadth is one lens. The outlook reads it alongside regime, valuation dispersion and sector rotation.

Outlook overview →