GlobalDairyTrade trading events are conducted as ascending-price clock auctions run over several bidding rounds. In each auction a specified maximum quantity of each product is offered for sale at a pre-announced starting price. Bidders bid the quantity of each product that they wish to purchase at the announced price. If the price of a product increases between rounds, to ensure their desired quantity a bidder must bid their desired quantity at the new, higher price. Generally, as the price of a product increases, the quantity of bids received for that product decreases. The trading event runs over several rounds with the prices increasing round to round until the quantity of bids received for each product on offer matches the quantity on offer for the product (as shown in the diagram below). Each trading event typically lasts approximately 2 hours.