Block Trade

A block trade is a large, privately negotiated transaction in securities — typically 10,000+ shares of stock or $200,000+ in bonds — executed through a broker's institutional desk or an off-exchange trading venue rather than through the public exchange order book. The defining characteristic is that the transaction is arranged off-exchange to avoid the price impact that a large order would cause if entered into the visible market.

Block trades are the primary mechanism by which institutional investors — pension funds, mutual funds, hedge funds, endowments — execute large position changes. When a fund needs to sell 500,000 shares of a stock, entering that order into the public market would immediately reveal the intent to sell, causing other traders to anticipate the downward pressure and sell ahead of it, driving the price down before the fund can exit. Executing through a block trade or an off-exchange trading venue eliminates that pre-trade visibility.

Block Trades vs Orders Split Across Exchanges

A block trade is a single negotiated transaction between two counterparties (or facilitated by a broker acting as principal). A large order can instead be split and routed to several public exchanges at once to fill quickly; it prints on the public tape as it fills, while a block trade is not visible until post-trade reporting. In options analysis, orders split across several exchanges are often read as more urgent than a single negotiated block; blocks may be directional or may be hedging/portfolio management activity.

Block Trades and Post-Trade Reporting

Many block trades in equities are executed away from the public order book and appear only in post-trade reports, which venue-level data providers aggregate after execution. TradeAI News does not ingest that data. What it measures is total volume against each ticker’s own baseline — a different reading, not an equivalent.