A block trade is a large, privately negotiated order executed away from the open market to avoid moving the price — often a sign of institutional positioning. It shows up in flow data.

How it works

When an institution wants to trade huge size, sending it to the open market would move the price against them (and reveal their hand). Instead, they negotiate a block — a large trade arranged privately (often via a broker or dark pool) at an agreed price, then reported to the tape. It lets big players move size with less market impact.

What it signals

Block trades in options are watched as potential institutional positioning — a large block can hint at a big player establishing a position. But like all flow, it’s ambiguous: it could be a directional bet, a hedge, or part of a complex structure. You usually can’t tell the intent, so it’s context, not a signal.

A block is institutions moving size quietly, then printing it. It marks where big money traded — but not necessarily why, or which way they really lean.

The takeaway

Block trades are large, privately negotiated orders that signal possible institutional activity — interesting flow context, but ambiguous. NoVo works at the level of dealer structure the flows build, not individual blocks. It’s useful market-structure literacy alongside sweeps.