In a securities class action case, the time frame referred to as the class period is the time during which the people in question held the stock referred to in the lawsuit. During this time, the illegal activity alleged in the lawsuit would have caused changes to the price of the stock and/or other things to occur, causing damages that the lawsuit is attempting to recover. In simple terms, the class period is the period of time when you would have had to own the stock in order to be eligible to join the securities class action case.
A securities class action lawsuit based on securities issues is often brought against a company who acted improperly, typically by committing some sort of fraud. The members of the securities class action are people who were adversely affected by the fraud and who thus have a legal claim for damages against the company.
The class period would likely be the time period during which the plaintiffs held the stock and during which the illegal activity took place. It is the time period in which possible money loss occurred due to the illegal actions of those being accused in the securities class action.
As an example, if the company illegally inflated the price of the stock, the class period would consist of the time during which the price was at this inflated number, and those involved in the lawsuit eligible for damages would be all those who bought stock during the class period. In other cases, the class period may extend over a much longer period of time, based on a determination that the fraudulent activity may have affected the pricing of the stock on a long-term basis.
If you believe you were the victim of securities fraud, consult with a lawyer to find out what your options are regarding joining a securities class action or filing a lawsuit yourself against the company that damaged your finances.