Stock Market Heat Map Today

US Stock Market Heatmap FAQ

Is this stock market heat map live?

Yes. Prices refresh about once a minute while the page is open, and the map re-renders on the server on the same cadence, so a first load already carries the current session. During the regular session the colors are today’s move against yesterday's close; before the open and after the bell the pre-market and after-hours toggles color the same blocks by the extended-session move. The timestamp above the map says which minute the prices came from, and the refresh button next to it fetches them again on demand.

Which sectors are moving the stock market today?

The by-sector table under the map ranks each sector group by the percentage points it adds to or takes from the map’s move. The Magnificent Seven tech giants (the Mag 7) and the chip makers get rows of their own. A group’s contribution is its cap-weighted move multiplied by its share of the map’s total market value, so a 1% move in technology counts for far more than a 5% move in utilities, and the column adds up to the map’s whole move. Clicking a sector title on the map zooms into that sector alone.

Is this the S&P 500?

No. It is our own list of the 500 largest US companies, rebuilt weekly from SEC filings and market prices, and it does not use S&P Dow Jones Indices’ membership list or sector data. The biggest companies are on both lists, so the two usually move within about a tenth of a percentage point of each other in a day. They differ at the edges: ours ranks by size alone, so it holds some large companies the index leaves out and leaves out some of the index’s smaller members. The market move quoted under the map is the percentage change in the SPY ETF’s price.

Is there a stock market heat map for tomorrow?

No: a heat map colors moves that have already happened, so tomorrow’s does not exist until tomorrow trades. The closest thing is the pre-market map, which this page switches to from 4:00am ET using the Pre-market toggle, and which colors each stock by its move against the previous close before the 9:30am open. Extended-session prints are thin and often fade at the open, so the pre-market map is a watchlist rather than a forecast. For what is scheduled to move these stocks next, the earnings calendar and today's timetable are linked below.

What do the colors on this heatmap mean?

Each block is colored by that stock’s percentage move for the selected timeframe and session: shades of green for gains, shades of red for losses, gray for unchanged or no data. Color intensity saturates at a move that is large for the timeframe: 3% on the one-day view, 6% over 5 days, 25% year to date, 50% over a year and 150% over five years, with the exact scale shown under the map. Every block also shows the signed percentage when it is large enough, and the popup always carries the exact figure.

Can this heatmap show 5-day, year-to-date, 1-year and 5-year performance?

Yes. The 1D / 5D / YTD / 1Y / 5Y toggle above the map recolors every block by its move over that window: 5D against the close five trading sessions back, YTD against the final close of last year, and 1Y and 5Y against the price one and five years ago (a company listed more recently is measured from its first close). Block sizes stay proportional to market cap on every view, and the pre-market and after-hours toggles apply to the 1D view.

How do I zoom into one sector?

Click a sector’s title bar. Hovering the title first highlights every block that belongs to the sector; clicking expands that sector to fill the whole map, with each company resized against its sector peers. Click the title again, press Escape or use the all-sectors button to zoom back out.

What decides the size of each block?

Block area is proportional to the company’s market value, so the biggest companies take the most space, and blocks are grouped into sectors sized the same way. The sectors are our own eleven groups, built from the industry code each company files with the SEC and corrected by hand where that code is out of date: Visa sits in financials, not business services. Membership and market caps were last refreshed on 2026-10-09.

How often do the prices update?

Quotes refresh roughly every minute while you keep the page open during market hours, and the page itself is re-rendered with fresh prices about once a minute, so the colors you land on are already current. The circular-arrow button next to the timestamp fetches the latest prices on demand. When the market is closed the map shows the last completed session.

Does this heatmap show pre-market and after-hours trading?

Yes. Use the Regular / Pre-market / After-hours toggle above the map. In pre-market mode colors show each stock’s pre-market change versus yesterday’s close; in after-hours mode they show the move since the 4:00pm ET close. Stocks that have not traded in the extended session show gray.

Which companies are on this heatmap?

The 500 largest US companies by market value, picked by our own rule. A company qualifies if it is listed on the NYSE or Nasdaq, files a US annual report (a 10-K), has its head office outside Canada and trades at least $50 million of stock a day on average. Funds, shell companies and limited partnerships are left out, and the companies that qualify are ranked by market value. Shopify is the one named exception: its head office is in Canada, but it trades mainly on Nasdaq. The list is rebuilt every Saturday from SEC filings and market prices. A company already on the map stays until it falls below 525th, and a newcomer joins once it reaches 475th, so the edge of the list does not change every week. Membership and market caps were last refreshed on 2026-10-09. The Nasdaq 100 heatmap is one tab over.