20 CFR § 416.203 - Initial determinations of SSI eligibility.
(a) What happens when you apply for SSI benefits. When you apply for SSI benefits we will ask you for documents and any other information we need to make sure you meet all the requirements. We will ask for information about your income and resources and about other eligibility requirements and you must answer completely. We will help you get any documents you need but do not have.
(b) How we determine your eligibility for SSI benefits. We determine that you are eligible for SSI benefits for a given month if you meet the requirements in § 416.202 in that month. However, you cannot become eligible for payment of SSI benefits until the month after the month in which you first become eligible for SSI benefits (see § 416.501). In addition, we usually determine the amount of your SSI benefits for a month based on your income in an earlier month (see § 416.420). Thus, it is possible for you to meet the eligibility requirements in a given month but receive no benefit payment for that month.