CVD resets: distinguish a new session from aggressive selling

Separate interval flow from accumulated level

For a declared trade classification, interval delta is buy-aggressor quantity minus sell-aggressor quantity. CVD adds these signed observations from an anchor. Changing the anchor changes the level even when every underlying trade remains identical. The difference between consecutive CVD values equals interval delta only when both values belong to the same uninterrupted accumulation.

A session is a configured boundary. Crypto trades continuously, so midnight UTC, an exchange session and a viewer’s local day need not coincide. Document the exact timezone and reset rule. Daylight-saving changes can move a local boundary relative to UTC; a timestamp without its timezone cannot fully identify the window.

Reconcile a discontinuity before interpreting divergence

At a reset, reconstruct the new session from its own trades and retain the final value of the old session separately. A continuous comparison can be formed by adding the old cumulative offset only when the two sequences have compatible units, coverage and classification. Do not bridge an actual data outage by pretending its unknown flow was zero.

When comparing two tools, align instrument, venues, measurement units, anchor and availability first. A product built from lower-timeframe candle estimates can disagree with a taker-flag calculation for reasons beyond resetting. The reset test isolates one cause; it does not establish that every other setting matches.

Worked example: a reset creates a false −6 reading

The constructed tape has four interval deltas: +5, −2, +4 and −1 base units. The first two belong to session A and the last two to session B. Continuous CVD is 5, 3, 7, 6. Session CVD is 5, 3, 4, 3 because B starts from zero.

Immediately before B begins, the old cumulative level is 3. The reset itself takes the display to zero without any trade. If a chart instead ended A at 10 and the first B interval closed at 4, subtracting displayed endpoints would report −6, even though the B interval contains +4 net aggressive quantity. Preserve the boundary rather than interpreting that subtraction as selling.

Zero may mean reset, missing data or balanced flow

A displayed zero is ambiguous without its status. A fresh anchor can legitimately start at zero; equal classified buy and sell quantity can produce zero delta; an unavailable feed should not silently become zero. Record data status alongside the value so an outage is not mistaken for a quiet or balanced market.