A “class period” is a specific period of time in which the unlawful conduct occurred. It defines the parameters of the class. For example, in a securities fraud class action, anyone who acquired the defendant’s stock during the class period is a member of the class and eligible to participate in recovery, in the event of success. If an investor purchased the stock outside the class period, then she would not be a member of the class. A class period may also apply to competition law, employment discrimination, or other types of cases. For instance, if a manufacturer artificially raised its prices in collusion with other manufacturers for a two-year time period, resulting in higher prices to indirect or direct purchasers, then the class period might run for the same two-year period.