Effective Date

date on which a contract or agreement becomes valid

Coming into force (also called enforcement or enactment) refers to the date and process by which legislation, or part of legislation, comes to have legal force and effect. It is important to note that the process whereby a Bill becomes an Act is an entirely different process from that of bringing the Act into force. A Bill, even though passed by law makers, which does not amount to an Act cannot be of any force and effect. Of course it may be that a country's law determines that on being passed by the law makers, a Bill becomes an Act without further ado. However, more usually, the process whereby a Bill becomes an Act is well prescribed in general constitutional or administrative legislation. This process varies from country to country, and from political system to political system
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In an interest rate swap, the date the swap begins accruing interest.