In finance, a block trade is a large, potentially market-moving trade on the stock market. By definition, buying or selling 10,000 shares of stock (with the exception of penny stocks) or $200,000 worth of bonds is considered a block trade.
Some investors and analysts look how many block trades are executed per day in a single company's stock for institutional investor activity. This measures how interested institutional investors are in the company. Since institutions generally dictate the direction of change of a company's stock price, block trades are especially helpful in determining the company's future performance.
