Many people think being a Joint Sponsor simply means signing a form and showing that your income is sufficient, without taking on any real responsibility. In reality, once you sign Form I-864 (Affidavit of Support), you take on a legally enforceable financial sponsorship obligation. 1. You may be required to provide financial support to the immigrant If the immigrant's income falls below the applicable legal threshold, the Joint Sponsor may be obligated to provide financial s