Professional trading concepts, in plain English

The real-time stream of buying and selling pressure — who is hitting the bid, who is lifting the offer, and at what size. Traded on by professional desks; mostly invisible to retail charting tools.

A candle chart where every bar's interior shows the bid-vs-ask volume traded at each price tick. Reveals absorption, exhaustion, and aggressor side at a glance — invisible on a regular candlestick.

The running sum of aggressive buy volume minus aggressive sell volume. Shows whether buyers or sellers are leaning on the market — and, when it diverges from price, who is quietly getting absorbed.

When a large resting order soaks up aggressive market orders without price moving — size hitting the bid or offer that simply doesn't break. Often marks where a move exhausts and turns.

Three or more consecutive footprint levels where aggressive buying (or selling) beats the opposite side by a set ratio (often 3:1+). One-sided force stacking through the book — frequently a precursor to a breakout.

A live ladder showing all resting buy and sell orders at every price level. The full visible book — what's offered, what's bid, what size, where the walls are forming or breaking.

A distribution of the time spent at each price across a session (TPO), surfacing the value area, point of control, and whether the auction is balancing or trending. The structural map under the candles.

The price range where ~70% of a session's activity traded — one standard deviation around the point of control. The zone the auction treated as fair; its high and low (VAH/VAL) are key acceptance/rejection references.

The aggregate gamma position of options dealers, projected across strikes. Predicts where dealers must buy or sell as price moves, and which strikes act as price magnets (walls) or repellents (the flip).

The price level where aggregate dealer gamma flips from positive (vol-dampening) to negative (vol-amplifying). The single most important regime line on the intraday chart — above it dealers fade moves, below it they amplify them.

The strike with the largest positive dealer call gamma. Dealers hedge by selling the underlying as price approaches, so it tends to act as resistance — a magnet and a ceiling traders mark on the chart.

The strike with the largest dealer put gamma. Dealers hedge by buying the underlying as price approaches, so it tends to act as support — the downside magnet that often holds into expiration.

Options expiring the same day they're traded — now roughly half of SPX option volume. 0DTE flow rebuilds the dealer-gamma surface intraday, which is why morning gamma levels go stale by lunch and the gamma flip can move during the session.