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Breadth

How broad is the participation?
Equal vs Cap Weight

The RSP/SPY ratio — the equal-weighted S&P relative to the cap-weighted index.

Formula RSP / SPYSource Yahoo Finance

equal_vs_cap_weight

How to read Rising = broad participation; falling = narrow mega-cap (Mag-7) leadership carrying the index.

% Above 200-DMA

The share of S&P 500 constituents trading above their 200-day moving average.

breadth_200dma

How to read >70% = strong breadth, <30% = weak; a divergence from the index warns of trend exhaustion.

Advance/Decline Line

Cumulative advance/decline line across the 11 S&P 500 sector ETFs, overlaid on the S&P 500.

How Running sum of net advancing minus declining components.Source Yahoo Finance

advance_decline

How to read A rising A/D confirms the trend; a falling A/D under a rising index flags narrowing participation.

McClellan Breadth

NYSE breadth momentum (the McClellan Oscillator) plus its running total (the Summation Index).

How EMA difference of net advances, then accumulated.Formula osc = 19d-EMA − 39d-EMA of (adv − dec); summation = Σ oscSource McClellan Financial (free)

mcclellan_breadth

How to read Two gauges of participation. The Oscillator (left axis) is the fast one — above zero advancers are outpacing decliners (breadth broadening), below zero the reverse; sharp spikes flag thrusts and washouts. The Summation Index (right axis) is its running total — the slow regime line: rising = a broadening, healthy advance, falling = participation narrowing. The classic warning is the index making new highs while the Summation rolls over — fewer and fewer stocks carrying the tape.

Descriptive: NYSE-composite breadth includes non-operating issues (closed-end funds, etc.); a technician's gauge, not a fundamental one.

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