10-Day Advance / Decline Lines

Each session, advancing stocks count +1, declining stocks −1 and unchanged stocks 0. Daily net breadth is 100 × (advancers − decliners) / all constituent issues. The plotted line is the simple average of the latest 10 trading sessions. Each issue has equal weight, regardless of market value. The chart shows participation, rather than the index’s price return or a cumulative A/D line.

The Technology group contains the S&P 500’s Information Technology constituents. It excludes Communication Services companies such as Alphabet and Meta. Dated iShares IVV holdings provide historical membership and sector classifications; daily State Street SPY and XLK holdings maintain membership going forward. Prices are individual Yahoo Finance split-adjusted closing prices, with cash dividends excluded. Acquired stocks no longer available from that provider use paired official IVV unit prices for the same security; EchoStar’s pre-entry close on 19 March 2026 comes from dated ITOT holdings. Cash, unlisted contingent-value rights, warrants, temporary when-issued interests and unclassified non-sector holdings are excluded. Index-fund holdings are a public proxy: fund rebalance dates and residual holdings can differ from an official index-membership feed. Member changes use the membership recorded for that session; historical observations do not use today’s constituents. Multiple share classes count as separate traded issues.

Fixed red/green reference bands are +16 to +32 / −16 to −32 for Technology and +13 to +26 / −13 to −26 for the S&P 500. These reproduce the reference layout’s approximate zone levels; they are not recalculated statistical bands. The original publisher’s full dataset and historical calibration are not public. This page is an independently calculated public-data reconstruction and may differ from its readings. Bespoke’s explanation describes this breadth study; StockCharts documents net advance/decline percent.

History begins in January 2025 after ten-session warm-up. Missing member prices invalidate that daily observation and every ten-session window containing it; they are never treated as unchanged or filled with synthetic returns. Membership publication can lag the market close. Automatic checks run at 06:25, 18:25 and 23:25 New York time on weekdays. Failed refreshes retain the last verified snapshot. Download observations, daily counts and source hashes.