Under U.S. law, every person who immigrates based. on a relative petition must have a financial sponsor. If you. choose to sponsor your relativeâs immigration by filing a. Form. I-130. , Petition for Alien Relative, you must agree to be the financial. sponsor and file an affidavit of support when the time comes for. actual immigration. If you do not meet the financial qualifications at. that time, you still must file a.