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§06 MARKET_BREADTH

OVERVIEW

Market Breadth answers one question: is the rally real, or is one mega-cap dragging the index? The panel batch-quotes a ~100-ticker large-cap universe — the same set the Heatmap uses — counts advancers versus decliners, sums up-volume versus down-volume, flags names at new 52-week extremes, and renders a single bullish/neutral/bearish sentiment read at the top.

MARKET_BREADTH

Note

The panel does not auto-refresh. Reload the browser tab whenever you want a fresh read. The cache window is short, so a hard refresh returns session-current numbers within seconds.

FEATURES

Sentiment Chip

The headline read is derived from the breadth percentage formula:

Breadth % = (advancers + unchanged × 0.5) / total × 100
Breadth % Sentiment Color
≥ 65% BULLISH Green
45–64% NEUTRAL Yellow
< 45% BEARISH Red

A/D Bar

A horizontal bar with a green segment (advancers) and red segment (decliners), proportional to count. Raw counts, the A/D ratio, and the percent split are displayed below the bar.

The A/D ratio is calculated as advancers / decliners, rounded to two decimals. If there are no decliners, the ratio equals the advancer count. A ratio above 1.00 means more names are up than down.

Volume Split Bar

A second bar showing cumulative session volume split between up-names and down-names. Use it to read conviction:

  • High up-volume on a moderate advancer count → buyers pressing hard into the green names
  • Low up-volume on a high advancer count → green names drifting up on light tape

Stat Grid

Field Description
ADVANCERS Count of universe symbols with positive netChange
DECLINERS Count with negative netChange
UNCHANGED Count at exactly zero change
A/D RATIO advancers / decliners, two decimals
BREADTH % Headline breadth read
CHECKED Total symbols that returned a usable quote
UP_VOL Cumulative session volume on names with positive change
DOWN_VOL Cumulative session volume on names with negative change
NEW_HIGHS Count trading within 0.25% of their stored 52-week high
NEW_LOWS Count trading within 0.25% of their stored 52-week low

Note

The server response includes above_50dma and above_200dma fields, but both currently return 0. These metrics are reserved for a future expansion and are not surfaced in the UI.

HOW TO USE

  1. Open /breadth. The panel batch-quotes the universe and renders within a couple of seconds.
  2. Glance at the sentiment chip in the header for the immediate one-line read.
  3. Read the A/D bar for the advancer/decliner split and ratio.
  4. Check the stat grid — confirm CHECKED is close to 100. A significantly lower number means some quotes failed to load and the sentiment chip may swing harder than usual.
  5. Read the volume split to judge whether buying or selling pressure is concentrated or broadly distributed.
  6. Reload the tab whenever you want an updated snapshot.

When to Use It

Moment What to look for
At the open Read the session tone — high breadth with a flat index means small-caps are leading
Mid-session Confirm or fade an index move — SPY +0.4% with breadth at 38% is a narrow mega-cap rally
At the close Log a regime snapshot — bullish-breadth-on-a-down-day or bearish-breadth-on-an-up-day are both journal flags

Tip

SPY up with breadth below 45% is historically a five-mega-cap rally. Use the volume split to confirm whether buying pressure is concentrated in those names before trading with the move.

KEYBOARD SHORTCUTS

Shortcut Action
None assigned Open /breadth directly via the URL or the §MARKETS sidebar group

Note

No dedicated keyboard shortcut is currently assigned to this panel.

LIMITS

  • Universe: ~100 large-cap US equities only. This is a directional read, not an NYSE-wide A/D line and does not survey the full Russell 3000.
  • New-high/new-low flags depend on stored 52-week values that may lag by one session for some names.
  • Not currently surfaced: McClellan Oscillator, NYSE NH-NL, % above 50DMA, % above 200DMA, and equal-weight vs. cap-weight comparisons. These are placeholders reserved for a future expansion.
  • Refresh cadence: Manual. No streaming or polling.
  • Volume tallies are session-cumulative and reflect directional skew, not precise dollar volume.
  • New-high/new-low proximity band is intentionally set at 0.25%. Strict equality would miss most session prints; a wider band would dilute the signal.
  • When the market-data feed is wholly unavailable, the UI surfaces a dedicated DATA_UNAVAILABLE state.

TROUBLESHOOTING

CHECKED shows ~60 instead of ~100

Some quotes failed to return — usually a partial timeout. The breadth math remains valid for the names that did come back, but the sentiment chip may swing harder than usual on a smaller sample. Refresh in 30 seconds for a fuller read.

Sentiment chip shows BEARISH but indices are green

Mega-cap concentration is the most common cause. A handful of large-cap names with heavy index weighting can lift SPY or QQQ while the majority of the universe declines. The breadth panel is counting names equally, not weighting by market cap — this divergence is the signal, not a data error.