When many sizable buy orders are bundled into a single sizable order and entered into the order book of a particular market at the same price, a buy wall is formed. Walls can be built by affluent individuals, business associations, or institutions. An order book is used in trading on cryptocurrency exchanges, where buyers and sellers list their respective asking and asking prices (bids and offers). Because they generate a large number of orders at the same price that must all be filled and transferred with a significant amount of money, buy walls effectively prevent market prices from decreasing. Buy or sell walls frequently emerge when significant holders (whales) of a cryptocurrency attempt to manipulate the market in their favor. In an effort to sway the markets, whale traders frequently erect purchase and sell barriers. Once substantial buy or sell orders appear in the order book, other traders usually place their orders quickly after the walls. For instance, extra traders who are keen to buy are more likely to do so at $10,000.01 or above if a substantial buy wall is erected at $10,000.00 for an asset. They act in this way because they believe there is a very small possibility that their orders—which cost $9,999.99 or less—would be filled if they were grouped together or concealed by a wall. The bulk of purchase and sell walls, however, merely appear temporarily and their orders are not entirely filled. Additionally, buy and sell walls constantly rise and fall with the state of the market. That is presumably the fault of trading bots or automated trading algorithms. Although less frequently, when a bearish market slide is exceptionally steep, purchase barriers can be quickly "eaten up," having all of their orders executed in a matter of seconds.