Against agency personnel in ex parte matters (that is, where an agency acts solely to confine its own discretion with no adverse effect on any party), guidance is binding against agency personnel. Guidance against the agency arises as a permissive power under the Housekeeping Act, 5 U.S.C. § 301, and a long line of Supreme Court cases originating with Accardi v. Shaughnessy, 347 U.S. 260 (1954). Classes of binding statements include: Sentences that state mandatory actions of agency personnel, for example "Agency staff must ..." or "The agency will ...—an agency can bind its employees via an employee manual, but cannot bind the public. When an agency's guidance promises "If a party before the agency does x, the agency promises to do (favorable) y." The agency is bound to keep such promises. When an agency guidance document interprets an ambiguity in a way that is favorable to a party before the agency in an ex parte proceeding, the party can rely on it, and no agency employee can back out. An agency can change its guidance with very little procedure (unlike a regulation), but as long as the guidance reads as it does, parties are entitled to rely on it for the three classes of promises listed above. In the late 1990s and early 2000s, many agencies attempted to bypass the APA's requirements for rulemaking by tucking rules that went beyond interpretation of ambiguity into informal documents like agency staff manuals and the like. This is simply illegal. The Executive Office of the President stepped in to stop bootleg rulemaking in 2007, and forbade this practice. Some agencies, for example, the U.S. Patent and Trademark Office, have nonetheless continued to defy the law, and state their formal refusal to implement the President's directive. Review by Office of Management and Budget and Congressional Review Act Executive Order 12866, which was issued in 1993, requires agencies (other than independent agencies) to submit proposed rules for reviews by the Office of Information and Regulatory Affairs if the rule meets certain criteria. Rules that are "economically significant" (meeting the criteria of "an annual effect on the economy of $100 million or more or adversely affect in a material way the economy") require a cost-benefit analysis. The Congressional Review Act passed in 1996 created a category of major rules, which are those that OIRA determines result in either: (1) "an annual effect on the economy