One Aggressor. One Passive. One Block.
ICB-BLOCK identifies when a single aggressive order absorbs a dominant passive position — structured and readable in the DOM, independent of tape activity.
![ICB-BLOCK live capture — DOM screenshot showing A[944]B block event at 7137.00, OOS 982 context, A[62]F diagonal imbalance on bid, and ICB Mobile confirmation](/images/concepts/icb-block-hero.avif)
ICB-BLOCK detected — A[944]B block event at 7137.00. Confirmed by OOS 982 context and ICB Mobile ▲3.
When an ICB event resolves as a single concentrated print against a passive participant holding substantial size on the opposite side, T2G classifies it as an ICB-BLOCK. This is not a sequence of fragmented fills — it is one structural encounter, bilateral and resolved in a single interaction. The DOM captures the imbalance. T2G surfaces it.
The ICB market order that initiated this interaction. Always aggressive — it crossed the spread to hit a passive position.
Total contracts executed in this ICB interaction. No minimum threshold — classification is structural, not size-based.
blockCount ≥ 1. The aggressive side resolved in a single dominant print against one passive participant. B = concentrated bilateral encounter.
The aggressive side resolves in a single dominant print. Volume concentrates against one passive participant. Classification: B. The encounter is direct and bilateral.
The aggressive side builds across multiple smaller prints. No single participant dominates the execution. Classification: F. The execution structure is sequential rather than concentrated.
ICB-BLOCK is not defined by size alone. A 50-lot block and a 944-lot block follow the same classification logic: one dominant aggressor print against one absorbed passive. The execution structure is what distinguishes it — not the raw volume.
T2G detects an ICB event — an aggressive order interacting with a resting passive participant at a specific price level.
The execution profile is analyzed. When the aggressive side resolves in a single dominant print (blockCount ≥ 1), T2G assigns the BLOCK classification.
The passive side is inferred: a single participant was holding substantial size and was fully absorbed in this interaction.
The ICB-BLOCK badge appears in the DOM column. The bilateral structure is readable in the order book — no tape confirmation required.
What is the difference between ICB-BLOCK and ICB-FRAG?
Both are ICB events, but they differ in execution structure. ICB-BLOCK means the aggressive side resolved in a single dominant print, absorbing one passive participant. ICB-FRAG means the aggressive side built across multiple smaller prints with no single dominant participant. Same event type — different structural profile.
Does ICB-BLOCK require a specific volume threshold?
No. The classification is based on execution structure, not raw volume. A 50-lot block and a 944-lot block are both ICB-BLOCK when the structural condition is met — a single dominant aggressor print absorbing the passive side.
Why is ICB-BLOCK readable in the DOM independently of tape activity?
T2G reads the Inside Print directly from order book interactions. The structural encounter between aggressor and passive is captured at the DOM level. The tape reflects the consequence — T2G identifies the structure at its source.
Can ICB-BLOCK appear alongside other T2G signals?
Yes. ICB-BLOCK is often reinforced by secondary signals such as OOS activity, ICB Cumulative buildup, or diagonal imbalance. Each signal is independent, but structural confluence tends to sharpen the overall read.
Does ICB-BLOCK imply a directional bias?
ICB-BLOCK describes a structural event — a bilateral encounter captured in the DOM. It provides microstructure context, not a directional forecast. T2G does not generate price predictions.
Read the DOM the way institutions do.
ICB-BLOCK is one of the exclusive detection capabilities built into T2G DOM. Available to all active license holders.