Supply and Demand are the key concepts of a market economy. Since market economy is based on exchange of goods and services for a value, for it to function there must be some goods and services to offer (supply) and people who are willing and able buy them (demand).
There is an important difference between classic Supply and Demand theory and Supply and Demand that applies to trading. In classic approach suppliers generally stay as suppliers in the process of exchange, however in trading we can’t identify certain participants as sellers or buyers. All participants in trading can be buyers or sellers at any point of time.More