ADD, VOLD and UVOL/DVOL

TICK is a heartbeat: fast, noisy, reset every instant. ADD and VOLD are the running tally of the day. They move slowly, they remember what happened since the open, and between them they answer the question that decides most intraday strategy: is this move broad and backed by volume, or is it a few names on thin trade?

ADD: the advance-decline difference

ADD is the number of NYSE stocks up on the day minus the number down on the day, updated continuously. With around 2,800 issues it can theoretically reach ±2,800; strong trend days print beyond ±2,000, ordinary days sit between -1,000 and +1,000.

+2500 ┤ ██████████████████  extreme up-trend day; 90%+ of stocks up
+1500 ┤ ██████████          strong; trend-day territory
 +500 ┤ ███                 mildly positive, mixed
    0 ┼─────────────────────────────────────────────
 -500 ┤ ███                 mildly negative, mixed
-1500 ┤ ██████████          strong; trend-day territory
-2500 ┤ ██████████████████  extreme down-trend day; capitulation

Two features matter more than the level:

Slope. ADD that climbs steadily from +600 at 9:45 to +1,800 by 11:00 is a broadening rally; more stocks are joining. ADD that peaks early and drifts back toward zero while the index holds its highs means participation is leaving even though price has not yet noticed.

Stability. On a trend day ADD picks a side early and stays there, usually beyond ±1,000 by mid-morning and never crossing zero. On a chop day it oscillates across zero, often several times.

VOLD: the up-down volume difference

VOLD is NYSE up volume minus down volume, in shares. Up volume is all the volume traded in stocks that are up on the day; down volume is the same for stocks that are down. VOLD tells you whether the day's money is behind the day's advancers.

The scale depends on total volume, so absolute levels change over years and across sessions. Read it the same two ways as ADD: slope and stability, plus one more.

Agreement with ADD. The powerful read is the pair.

The second row is the classic "index up, nobody cares" morning that reverses after lunch. The third row is the megacap mask in real time.

Key idea: ADD counts the stocks, VOLD counts the shares. A move confirmed by both is broad and funded; a move confirmed by only one is worth less than it looks.

UVOL, DVOL and the ratio

UVOL and DVOL are the two halves of VOLD, available separately. Their ratio removes the scale problem:

up/down volume ratio = UVOL ÷ DVOL

A "90% up-volume day" is one where up volume is at least 90% of total volume, which is a ratio of 9:1. These days are rare, and clusters of them after a decline have a decent historical record as the start of rallies; Module 3 comes back to that in the breadth-thrust lesson. The same ratio computed on a daily close is one of the oldest breadth statistics there is.

Reading the three together, by the clock

A rough map of a trend-up day:

 9:30  ADD +400   VOLD small +    TICK bursts to +900 at the open
10:00  ADD +1100  VOLD building   TICK dips to -200 get bought
11:00  ADD +1600  VOLD strong +   TICK mostly +200 to +800
12:30  ADD +1500  VOLD strong +   TICK quiet, lunch
14:00  ADD +1800  VOLD new high   TICK +1000 on a breakout
15:30  ADD +2000  VOLD new high   TICK positive into the close

And a chop day:

 9:30  ADD +600   VOLD +          TICK +800 then -700 in ten minutes
10:00  ADD -200   VOLD flat       TICK oscillating
11:00  ADD +300   VOLD +          index at the open price again
12:30  ADD -100   VOLD −          nothing has held
14:00  ADD +400   VOLD flat       range still intact
15:30  ADD -50    VOLD −          closes near the open

The trend day is obvious by 10:30 to 11:00. That is not late; a trend day still has two-thirds of its range ahead at that hour. The chop day is also obvious by then, and the correct response is smaller size and faded extremes, or no trading at all.

Nasdaq versions

All three exist for Nasdaq-listed stocks too. Tech-heavy days can show a strong Nasdaq ADD with a flat NYSE ADD, or the reverse. If you trade Nasdaq 100 futures, watch the Nasdaq set; if you trade S&P futures or NYSE stocks, watch the NYSE set; if you trade both, watch both and note when they disagree, because a disagreement usually means a sector story rather than a market story.

Failure modes

• Reading the level without the slope. ADD +1,200 that was +1,900 an hour ago is a deteriorating tape, not a strong one.
• Ignoring VOLD. ADD alone is easily fooled by thin, broad drifts. Volume is the confirmation.
• Expecting exact thresholds. ±1,500 on ADD is a starting point. Lesson 4 explains how to calibrate for your market and era.

Try it: For the next five sessions, write down ADD and the UVOL/DVOL ratio at 10:30 and at the close. Label each day trend-up, trend-down or chop from the close's location in the day's range. Check how often the 10:30 reading already pointed to the right label.

Recap

• ADD is NYSE advancers minus decliners on the day; VOLD is up volume minus down volume.
• Read both by slope and stability, not just level; trend days pick a side early and hold it.
• Agreement between ADD and VOLD confirms a broad, funded move; disagreement flags fragility or narrowness.
• UVOL ÷ DVOL removes scale; 9:1 is a 90% up-volume day, a rare and historically meaningful print.
• Watch the Nasdaq set if you trade Nasdaq products, and note when the two exchanges disagree.