A restricted stock refers to unregistered shares of ownership in a corporation that are issued to corporate affiliates, such as executives and directors. Restricted stock is nontransferable and must be traded in compliance with special Securities Exchange Commissions (SEC) regulations. It typically becomes available for sale under a graded vesting schedule that lasts several years.
Pure or perfect competition is a theoretical market structure in which the following criteria are met: all firms sell an identical product (the product is a "commodity" or "homogeneous"); all firms are price takers (they cannot influence the market price of their product); market share has no influence on price; buyers have complete or "perfect" information – in the past, present and future – about the product being sold and the prices charged by each firm; resources such as labor are perfectly mobile; and firms can enter or exit the market without cost.