U.S. companies involved in federal litigation will now need to track e-mails and instant messages generated by employees to comply with new rules that take effect Friday.

The amendments to Federal Rules of Civil Procedure will require companies and other entities involved in federal litigation to include electronically stored information as part of the discovery process, when evidence from both sides is shared.

The rule changes make it important for companies to know when and where their data is stored.

Legal experts say federal and state courts are already requiring relevant electronic documents to be produced during discovery, but the new rules will codify the practice.

James Wright, director of electronic discovery at Halliburton Co., said companies now face higher costs and will have to track everything from e-mail to less accessible information such as digital photos of work sites on employee cellphones to information on removable memory cards.

The changes don't mean companies will have to keep e-mails in perpetuity, however. A "safe harbour" rule in the amendment offers some protection to companies who fail to comply, as long as they took reasonable steps to preserve potentially discoverable material or the loss of information was part of a routine function of the information system.

The rules could double the amount of businesses that offer electronic storage or recovery services, Wright said.

Canadian securities firms are already bound to retain all correspondence, including e-mail, for five years under their industry rules.

With files from the Associated Press