What On-Balance Volume (OBV) measures
If today's close is above the prior close, today's volume is added to the running total. If it is below, volume is subtracted. An unchanged close leaves the total unchanged.
The starting value is arbitrary, so OBV is interpreted through direction, swings, and comparison with price rather than the displayed total itself.
How to read On-Balance Volume (OBV)
Rising price with rising OBV describes price and cumulative volume direction moving together. If price makes a new swing high while OBV does not, the mismatch is commonly studied as a divergence.
Divergence can persist and may resolve through either price or OBV. Treat it as evidence to investigate rather than an immediate reversal signal.
AptiStockX default settings
AptiStockX renders one OBV curve in a dedicated pane using the packaged desktop color, width, and line style.
The interactive example starts with only On-Balance Volume (OBV) enabled. It intentionally uses AptiStockX's synthetic SPY demo data, so the page teaches the charting workflow without presenting live market information.
A practical AptiStockX workflow
Zoom out and compare major OBV swing points with price swing points. Focus on sequence and slope instead of small one-bar changes in the cumulative total.
Inspect large volume spikes carefully because one session can permanently shift every later OBV value. Determine whether the line's direction after that event remains informative.
Limitations and interpretation
OBV assigns all volume to one direction based only on the close-to-close change. It does not know how activity was distributed within the bar.
Data corrections and isolated volume events can create lasting level shifts. Cross-security comparison of absolute OBV values is not meaningful.
Technical indicators summarize historical data. They do not predict outcomes, provide personalized investment advice, or replace independent research and risk management.
AptiStockX is a native desktop stock charting and analysis application for self-directed traders and researchers who want local data, native speed, and a durable workflow.