What are examples of cases of ultra vires?

Ultra vires refers to actions taken by an entity that are beyond its legal power or authority. Examples include a corporation entering into a contract that its charter explicitly forbids, or a government agency exceeding the powers granted to it by legislation. Another instance could be a nonprofit organization using its funds for activities unrelated to its stated mission, violating its purpose as defined in its founding documents. In each case, the actions can be challenged and potentially deemed invalid in a court of law.