How long does a trade secret last?

Theoretically, a trade secret can last forever. As long as its owner continues to keep the information secret, and as long as that secrecy continues to make the information economically valuable to its owner, the information is protectable as a trade secret. This is one of the major differences between trade secrets and other forms of intellectual property, such as copyrights and patents, which are only afforded protection for a specified duration of time.