Stock exchange dark pools
JPMorgan’s securities unit also runs JPMX, a dark pool that matches shares in a more traditional manner, within the spread of the best bid and offer prices shown on public stock exchanges like When they receive an order, the price of the stock is adjusted and everyone with a data feed sees it. So, if a lot of people want to sell a stock, the price goes down, and if a lot of people want to buy, it goes up. Dark pools are the exact opposite of that. They report data only after a trade has occurred.