The Siren is awarded to you for life if you are an individual entrepreneur IS. If you are the head of several companies as businesses (legal entities), you have a Siren number for each of them. The Siren may only be removed in certain cases: For an individual entrepreneur (IS): on the death of the entrepreneur or on a cessation of activity For a business: during a liquidation In the event of a change in your situation (or that of your company) or a change in the main activity: you must report each change to Single window for company formalities, regardless of the legal form of your company. Service en ligne : Company Formalities Window En savoir plus sur Entreprendre.Service-Public.fr