Follow-Through Day Detection

A follow-through day is the point where a beaten-down market shows the first real evidence that sellers have been overwhelmed by buyers. In TradersLab it is defined precisely: if the market makes a higher low while in a confirmed downtrend, and the Global Daily Breadth score shows a breadth thrust reading, then it is treated as a follow-through day (FTD) and a potential market bottom.

Both halves matter. The higher low tells you price has stopped making new lows; the breadth thrust tells you the bounce is backed by broad participation rather than a handful of stocks. The mirror case is a potential top — a lower high in a confirmed uptrend paired with a GDB distribution reading.

The Global Daily Breadth score is a weighted, standardized composite of daily price change, net advance/decline ratio, up/down volume ratio, net new 52-week high/low ratio and the 4% up/down momentum ratio, normalized against the last year of readings onto a -100 to +100 scale. A reading above +80 is a Breadth Thrust — excessive, broad buying — and below -80 is Distribution.

That +80 thrust is what confirms a follow-through day. Because GDB rolls up the whole day's internals into one number, a thrust means advancers, up-volume, new highs and the 4% up/down ratio all surged together — the kind of broad, forceful buying that tends to accompany a genuine turn rather than a dead-cat bounce.

TradersLab wraps the signal in a full FTD dashboard that runs on both the Nasdaq and the S&P 500. A rally-day counter marks the attempted low as Day 0 and counts the sessions since, so you always know how far into a rally attempt the market is, and an FTD Status indicator tells you at a glance whether a valid follow-through day has printed. Alongside it, a distribution-day count tracks the heavy-selling days stacking up against the rally.

A Power Trend state summarizes the trend regime — it turns on when the shorter EMA holds above the longer SMA — to confirm that a rally has matured into a durable uptrend. The chart makes all of this visible with overlays: the 21 EMA and 50 SMA, plus markers flagging each follow-through day and each distribution day directly on price, so the count and the context sit in one view.

Because the same GDB reading is computed live for several indices, Intraday GDB lets you watch a potential follow-through day build in real time instead of waiting for the close. A positive, strengthening intraday reading signals broad upside participation and a more sustainable rally; comparing it across the NYSE Composite, equal-weight S&P 500, equal-weight Nasdaq 100 and Russell 2000 shows which index is leading the recovery and which is lagging.

Watch the relationship between price and breadth for early confirmation: price turning up while GDB improves supports the bottoming case, whereas price bouncing while GDB stays flat suggests the move lacks participation and may fail.