The Affidavit of Support is legally required for the petitioning sponsor for many family-based and some employment based immigrants to show the intending immigrant will have adequate means of support, when planning to immigrate to the U.S. The purpose of the process is to prove that the intending immigrant has adequate means of financial support and is unlikely to become a public charge. A “petitioning sponsor” is a person who has filed an immigrant petition, which has been approved by USCIS.