Not every session builds a clean bell curve. When one side of the auction does most of the work, the profile leans, and two of the most common leaning shapes are the P-shaped profile and the b-shaped profile. Read them right and they tell you whether a move is a fresh trend or the exhaust of an old one, before the next candle prints.
What a P-shaped profile looks like
A P-shaped profile has a fat bulge of volume near the top and a thin, stretched tail running down below it. Trace the outline and it resembles a capital P: the round part sits high, the stem drops beneath.
The thin lower tail is the story. It means price ran up quickly from below, transacting little on the way, and then found acceptance up high where the bulge formed. Two common causes:
- Short covering. Trapped shorts buy back to close, forcing price up fast; the rally is fueled by exits, not fresh conviction. Once the covering is done, the fuel is gone.
- A move that found value higher. Genuine buyers pushed price into a new area and the market accepted it, building the bulge as new fair value.
Context decides which. A P-shape after a sustained downtrend often marks a pause or exhaustion of the down move, short covering that may not lead anywhere. A P-shape in an established uptrend is more likely genuine acceptance higher and a continuation base.
What a b-shaped profile looks like
A b-shaped profile is the mirror: a fat bulge near the bottom with a thin tail stretching up above it, tracing a lowercase b. The bulge sits low, the stem rises.
The thin upper tail means price fell fast from above with little trade, then found acceptance down low. The usual drivers:
- Long liquidation. Trapped longs sell to exit, dumping price down quickly; the decline is driven by forced selling rather than aggressive new shorts.
- A move that found value lower. Real sellers pushed price into a new area and the market accepted it there.
Same context rule. A b-shape after a strong uptrend often signals a pause or exhaustion of the up move, long liquidation that may stall. A b-shape inside a downtrend is more likely acceptance lower and a continuation.
Why the shape matters
The value of these shapes is that they separate who is driving from where price ended up. A market can close higher on the day and still print a P-shape born of short covering, which is a very different thing from a market closing higher on genuine buying. The bulge shows where business actually got done; the thin tail shows the direction price traveled to get there without commitment.
This is also where the P and b shapes differ from the balanced case. When neither side dominates, the profile forms the symmetric bell curve of a normal distribution, a D-shape, and the read is mean reversion around a central point of control. P and b shapes are the skewed cousins: one-sided auctions that lean instead of balancing.
How to trade P-shaped and b-shaped profiles
The setups follow from the context.
P-shape as trend pause (fade risk). After a downtrend, a P-shape that formed on short covering is prone to failing. Price often rotates back down once the covering dries up. Watch the thin lower tail: if price re-enters it, there is little volume to hold it, and it can fall fast back toward the bulge’s low edge or below. On the ES, a P-shape with its bulge around 5,410 to 5,420 after a morning of selling, followed by cumulative delta rolling over at the highs, is a classic setup to fade back into the tail.
P-shape as continuation (with an uptrend). In an uptrend, treat the bulge as a new acceptance zone and its lower edge as support. Pullbacks into the top of the bulge that hold, confirmed by absorption on the footprint chart, offer continuation entries.
b-shape as trend pause (fade risk). After an uptrend, a b-shape built on long liquidation often stalls and reverses back up once forced selling ends. If price pokes into the thin upper tail and stalls with buyers stepping in, that tail can get filled quickly on the way back up.
b-shape as continuation (with a downtrend). In a downtrend, the bulge is new acceptance lower and its upper edge is resistance. Failed rallies into that edge give continuation shorts.
The single most useful confirmation across all four is cumulative delta at the thin tail. A P-shape rolling over with negative delta divergence at the highs, or a b-shape basing with positive divergence at the lows, turns a shape into a trade. Trapped participants are the engine of both patterns, and their forced exits are what fill the thin tails.
Reading the shape as it develops
You do not have to wait for the session to close to use these. The profile builds in real time, so you can watch a bulge form and a tail stretch as the auction unfolds. A developing P-shape mid-session, with volume stacking up top and a thin zone opening below, tells you the current up-move is finding acceptance rather than just spiking.
Pair this with the volume profile levels themselves: the bulge is effectively a high volume node, an area of acceptance that will act as support or resistance later, while the thin tail is a low volume node that price travels through fast. Where the profile’s point of control ends up, and whether it keeps migrating in the trend direction, tells you whether the lean is holding or the auction is rebalancing. For the full framework that ties these shapes to footprint and delta reads, see the order flow trading guide.
Frequently Asked Questions
What is the difference between a P-shaped and a b-shaped profile?
A P-shaped profile has a volume bulge at the top with a thin tail below, produced by price running up fast (often short covering) and finding acceptance higher. A b-shaped profile is the mirror: a bulge at the bottom with a thin tail above, produced by price falling fast (often long liquidation) and finding acceptance lower. P leans up, b leans down.
Does a P-shaped profile mean price is going up?
Not necessarily. A P-shape shows price found acceptance higher, but the cause matters. In an uptrend it often means genuine acceptance and continuation. After a downtrend it frequently reflects short covering, which can exhaust and reverse back down. Read the trend context and check cumulative delta at the highs before assuming direction.
How do I trade a b-shaped profile?
Use the context. After a strong uptrend, a b-shape built on long liquidation often stalls and reverses back up once forced selling ends, so watch the thin upper tail for a fast fill. Inside a downtrend, treat the bulge as new acceptance lower and fade failed rallies into its upper edge. Confirm with a positive delta divergence at the lows.
What causes the thin tail in a P or b profile?
The thin tail forms where price moved fast with little volume, usually driven by trapped traders exiting. In a P-shape the thin lower tail comes from shorts covering, which lifts price quickly through prices where little business is done. In a b-shape the thin upper tail comes from longs liquidating. Because so little traded there, price tends to travel back through the tail quickly.