What Does Real-Time Market Data Mean?
Real-time describes data delivered with little delay under a particular feed and entitlement; it is not a universal guarantee.
Read the draftHow Market Watch 360 Calculates
How Market Watch 360 Updates Its Views
Learn which inputs can change a market view and why card, chart, and basket readings may update on different schedules.
Draft updated · owner review pending
A dynamic desktop view can change when prices, quotes, session state, selected securities, or calculation references change. The precise cadence of each Market Watch 360 panel must be checked against the current application build; this draft explains the inputs without promising a uniform update rate.
Three different clocks
A trade or quote has a source timestamp. A chart bar represents a defined interval and may still be forming. An index or ETF weight reference comes from a dated methodology or holdings file and is not a tick-by-tick feed. Showing all three on one screen is useful only when their sources and timing are clear.
A selected basket can change the answer
Switching from All to Up, Down, Impact, or Biggest Movers changes which securities are visible and how they are ordered. The stock-level readings may update as data arrive, while membership or sorting may refresh according to the application's own rules. Do not assume every displayed number changed at the same instant.
An illustrative update
Suppose a selected stock moves from +1% to +2% while its dated reference weight remains 5%. Its simplified cap-weight contribution changes from +0.05 to +0.10 percentage points. If another selected stock turns negative at the same time, the net view can move less than the first card suggests. This is a hypothetical arithmetic example, not an observed session.
Key takeaway
Treat the app as a continuously updating analysis workspace, while reading each panel's feed, interval, reference date, and selected universe. Exact product timing and control behavior remain application verification items.
Sources and further reading
- Alpaca Real-time Stock DataStock stream messages, feed types, and delayed SIP
- Alpaca Market Data FAQFeed coverage, entitlements, and recent historical data
- S&P DJI Index Mathematics MethodologyOfficial index calculation and divisor reference