US Market · Heatmap

Prices and % change from Yahoo Finance, refreshed about once a minute during US market hours by a GitHub Actions workflow; this page re-reads board_data.json every 30 seconds while open.

Each sector row shows two different things, and they are meant to disagree. The coloured figure is an equal-weighted average of that sector’s S&P 500 constituents — a breadth measure, every name counting once. The bar beside it is the sector’s Select Sector SPDR and where it sits in its own day range — cap-weighted, so a few giants dominate it. The gap between them is the information: on 5 October 2026 Consumer Discretionary read +0.02% equal-weighted against +1.13% for XLY, which is Amazon and Tesla carrying a sector whose average name went nowhere.

All eleven GICS sectors have an exact, liquid fund, so a missing bar there means a fetch failed rather than that no index matches — and it says so. ETF groups have no fund of their own, so they fall back to the same constituent-derived envelope the Indian board uses for its eleven sectors with no matching NSE index: each member’s own day low and high as a % move from its own previous close, averaged equal-weight. That bar is drawn muted and dashed on purpose. It is an envelope, not an index — it treats every member’s low as simultaneous, which no real index does — so read it as “how far the average member travelled today”, never as a level. Click an ETF group to open it and each member shows its own real traded day range, drawn by the same component a sector row uses. No member is promoted to “represent” its group — the real ranges belong to the funds, so that is where they are shown.

Corporate actions are withheld, never guessed. A name trading across a split or spin-off today has its percentage shown as NA and is left out of its sector average for that session, because the raw print spans the event rather than measuring a move. It is not adjusted to an estimate: only the historical series has a ratio worth dividing out, and the next session is right on its own. A large move with no corporate event behind it is never touched — on this market those are almost always real. Tile colours use the per-stock scale in the legend; sector figures use a finer scale suited to averages. Tap any tile for that security on Yahoo Finance.