This is a market situation wherein sellers are outnumbered by buyers by a big margin and the quantity of goods available for sale becomes far less than the quantity demanded. During boom as demand outstrips supply, the situation can often be seen across. For e.g. in summer, there is a huge demand for mangoes. In a certain location where there are just two mango sellers and the demand is extremely high for the same, then that would be a seller's market. Since the demand is high, the sellers will be able to charge a high price for mangoes and get better sale conditions.