20 CFR §404.623

1. (a)Presumed filing for husband's or wife's benefits. If you file an application for old-age benefits, you are presumed to have filed an application for husband's or wife's benefits in the first month of your entitlement to old-age benefits, if—
   1. (1)Your old-age benefits are reduced for age because you choose to receive them before you reach full retirement age (as defined in § 404.409); and
   2. (2)You are eligible for either a husband's or a wife's benefit for the first month of your entitlement to old-age benefits.
2. (b)Presumed filing for old-age benefits. If you file an application for a husband's or a wife's benefit, you are presumed to have filed an application for old-age benefits in the first month of your entitlement to husband's or wife's benefits if—
   1. (1)Your husband's or wife's benefits are reduced for age because you choose to receive them before you reach full retirement age (as defined in § 404.409); and
   2. (2)You are eligible for old-age benefits for the first month of your entitlement to husband's or wife's benefits.
3. (c)Exception. Paragraph (b) of this section does not apply if you are also entitled to disability benefits in the first month of your entitlement to husband's or wife's benefits. In this event, you are presumed to have filed for old-age benefits only if your disability benefits end before you reach full retirement age (as defined in § 404.409).