Also called block, big print
Block trade
A single trade far larger than the tape's usual print, typically an institution moving size. The paper desk marks any print five times the running median.
Updated 2026-09-16
A block is a single print far larger than the tape's usual size. Institutions move in blocks because they have to; a fund that needs a million shares cannot buy them a hundred at a time. Many blocks are negotiated off the visible book and printed afterward, which is why a block can appear on the tape at a price the book never showed.
On the desk's tape a print five times the running median gets a mark. Read it with the tick rule colour: a marked print at the ask is size being bought, at the bid size being sold, and a string of them at one price is an institution working an order it has not finished. Then look at what price does after, because the block itself is already done.
See also
- Time and sales — The running list of executed trades: time, price, size. Reading it is watching who is actually paying up, as opposed to the book, which is what people say they would do.
- Liquidity — How easily something can be sold near its quoted price. A liquid stock absorbs your order; an illiquid one moves against you as you fill it.
- Order imbalance — The share of the displayed size sitting on the bid versus the ask. Bid heavy says buyers are queued; ask heavy says sellers are. A lean, not a forecast, and it changes every second.
Educational content, not investment advice. Angie explains how a valuation is built so you can judge it yourself. What you do with that is your call.
