Biotech Sector Heatmap

A biotech stock heatmap is a single picture of how the sector traded in a session. It covers companies that develop human therapies; medical device makers, diagnostics firms, hospital operators, insurers and animal-health companies are left out, because they have no therapeutic area to sit in. Each company is drawn as a tile, the size of the tile is set by its market capitalisation, and the colour is set by how far its share price moved. Large green tiles are big companies that rose, small red tiles are smaller companies that fell. Because the whole US-listed biotech and pharma universe is drawn at once, you can tell in a glance whether a move is broad sector weakness or one company reacting to its own news.

A single mixed map is dominated by the largest companies, so a sharp move in a small-cap clinical-stage biotech becomes a tile too small to notice. Splitting the view into a gainers map and a losers map means the biggest movers on each side are both readable, which is where catalyst-driven activity usually shows up. Each side is still sized by market cap, so you keep the sense of scale within that group.

Tile size uses market capitalisation, which is shares outstanding multiplied by the current share price. Share counts are taken from the cover page of the most recent quarterly and annual reports each company files with the SEC, so the figure follows dilution as it is reported rather than staying fixed. This matters in biotech, where clinical-stage companies frequently issue new shares to fund trials and a stale share count would make a company look smaller than it now is. For a therapeutic area tile, a company that works in several areas has its market cap divided between them in proportion to how much of its drug pipeline sits in each, so a large diversified pharma counts towards oncology only as far as its oncology programmes justify. Without that, a company active in fifteen areas would be counted at full value fifteen times and every area would look the same size.

Prices move through the regular trading session, which runs from 09:30 to 16:00 Eastern time, and settle once the session closes. Percentage changes shown on the tiles are measured against the previous close. Pre-market and after-hours activity is excluded from the session change, so a biotech that gapped on overnight news will show the move once regular trading is under way rather than before it.

Yes. The filters above the maps let you narrow to a therapeutic area or industry group, so you can look at oncology, neurology and central nervous system, immunology, rare disease, infectious disease, or cardiovascular and metabolic names on their own. You can also restrict the view by market-cap tier to separate micro-cap and small-cap clinical-stage biotech from large-cap pharma, which usually behave very differently on the same day.

Large single-name moves in biotech are normally caused by a company-specific catalyst rather than sector sentiment. The usual causes are a clinical trial readout, an FDA decision such as an approval or a Complete Response Letter, an advisory committee vote, a regulatory designation, or a financing that dilutes existing holders. Small-cap biotech reacts hardest because a single asset can represent most of the company's value. Selecting any tile opens that company profile, where its catalyst history and upcoming events are listed.

A general market heatmap groups companies by broad sector, so all of healthcare lands in one block and drug developers sit next to insurers and device makers. A biotech heatmap instead groups by therapeutic area, which is the level at which biotech actually trades: positive data in one oncology programme often lifts companies pursuing the same target, and a safety signal can weigh on an entire drug class. Grouping by disease area rather than by generic sector is what makes those read-across moves visible.