# Market Monitor Methodology

Market Monitor is a Stockbee-style U.S. stock-market breadth tracker calculated independently from a local archive of daily OHLCV data. The published page is a static, read-only data product; it is not scraped from a website and it is not investment advice.

## Published resources

- [Dashboard](./)
- [Aggregate JSON snapshot](./market-monitor.json)

The JSON snapshot is the machine-readable contract. It includes `schemaVersion`, the session range, explicit column definitions, interpretation notes, and rows ordered newest first.

## Fields

| JSON key | Meaning |
| --- | --- |
| `date` | U.S. market session represented by the row. |
| `up_4pct` | Liquid securities up at least 4% on the session under the monitor's volume tests. |
| `down_4pct` | Liquid securities down at least 4% on the session under the monitor's volume tests. |
| `ratio_5d` | Five-session total of `up_4pct` divided by `down_4pct`. |
| `ratio_10d` | Ten-session total of `up_4pct` divided by `down_4pct`. |
| `up_25pct_quarter` / `down_25pct_quarter` | Securities at least 25% above a 65-session low or below a 65-session high, respectively. |
| `up_25pct_month` / `down_25pct_month` | Securities up or down at least 25% over the 20-session comparison window. |
| `up_50pct_month` / `down_50pct_month` | Securities up or down at least 50% over the 20-session comparison window. |
| `bull_34_13` / `bear_34_13` | Securities at least 13% above a 34-session low or below a 34-session high, respectively. |
| `x10atr` | Securities with a daily high-low range at least 10 times the smallest range in the prior 14 sessions. |
| `t2108` | Local T2108-equivalent participation percentage: eligible stocks above their 40-day average. |
| `universe` | Listed-universe securities with a valid bar on the session. |
| `sp500` | SPY ETF closing price, included as market context. |

## Reading the table

Rows are newest first. Green cells represent stronger upside breadth or ratios above 1; red cells represent stronger downside breadth or ratios below 1; gold indicates range expansion. The exact continuous heat scales are part of the generated visual presentation. The `t2108` field is explicitly labeled as a local equivalent because the reconstructed eligible universe differs from proprietary vendor universes.

## Data and caveats

The daily pipeline is freshness-gated and publishes only after the expected session has sufficient data coverage. Historical counts can differ from another provider because universe membership, survivorship, corporate-action history, and vendor definitions differ. Aggregate values are for market awareness and research, not individualized financial advice.