Stock heat map: S&P 500 by market cap
483 S&P 500 stocks at the 22 Oct 2026 close: the bigger the rectangle, the bigger the company; the greener, the higher it rose that day; the redder, the lower it fell. Weighted by market cap the index moved −1.16%, with 320 stocks up and 162 down. End-of-day data, grouped by sector.
S&P 500 heat map by sector, 22 Oct 2026
Market cap is the last close times the diluted share count of the latest filing. 483 of 500 covered companies are shown; stocks without a latest-session price or a share count are left out. Colours saturate at ±3%.
Sector moves, 22 Oct 2026
| Sector | Stocks | Cap-weighted change |
|---|---|---|
| Information Technology | 75 | −2.88% |
| Communication Services | 17 | −3.01% |
| Health Care | 60 | +1.44% |
| Consumer Discretionary | 47 | −1.72% |
| Financials | 71 | +1.03% |
| Industrials | 81 | −0.62% |
| Consumer Staples | 29 | +3.18% |
| Energy | 20 | −0.66% |
| Utilities | 31 | +2.02% |
| Real Estate | 29 | +0.95% |
| Materials | 23 | +0.38% |
The sector change is the market-cap-weighted average of its stocks' daily changes, so the largest companies count the most.
Biggest gainers
| Stock | Change |
|---|---|
| ALLE Allegion | +11.02% |
| ROP Roper Technologies | +9.73% |
| LEN Lennar | +8.69% |
| BX Blackstone | +8.38% |
| GIS General Mills | +8.01% |
Biggest decliners
| Stock | Change |
|---|---|
| MRNA Moderna | −17.57% |
| COHR Coherent | −12.51% |
| LRCX Lam Research | −11.76% |
| LITE Lumentum | −11.54% |
| FLEX Flex | −11.08% |
How to read the heat map
Because rectangles are sized by market value, a few very large companies take up much of the map, and the index moves mostly with them. Compare the colour of the big tiles with the sector averages above: a sector can be mostly green by count and still fall if its largest names dropped. The colour covers a single trading day and says nothing about longer trends or about value.
For longer lists of the day's movers see gainers and losers; the full list of components with weights is on S&P 500 components, and Market Compass reads the wider market with seven signals.
Frequently asked questions
What is a stock heat map?
A stock heat map draws many stocks at once as rectangles. Here the size of each rectangle is the company's market capitalisation and its colour is the stock's price change over the last trading day: green for a rise, red for a fall, and a darker shade for a bigger move. Stocks are grouped by sector, so you can see at a glance which sectors and which big companies drove the day.
How is the S&P 500 heat map built?
Each company is sized by market cap, calculated as the last closing price times the diluted share count from its latest SEC filing. The colour is the change between the last two closing prices, shown on a scale that is fully saturated at 3% up or down. Hover over a rectangle for the name, price, change and market cap, or click it for the stock page.
Is the heat map live?
No. It is built from end-of-day prices after the US market closes, so it shows the move of the last completed session (22 Oct 2026), not intraday changes.
Why are some S&P 500 stocks missing?
We show 483 of the 500 companies we cover. A stock is left out when it has no price from the latest session, no share count in our filings data yet (for example a recent spin-off or listing) or a one-day move above 60% that is usually a data or corporate-action artefact.
Does a bigger rectangle mean a better stock?
No. Size only shows how large the company is by market value. Colour shows one day of price change. Neither says whether a stock is cheap or expensive; for that see the X-Ray Score and fair value range on each stock page.
Related
Educational information, not financial advice. End-of-day data; price changes are for one trading day.