26 CFR §31.3121(i)-2 — (i)-2 Computation of remuneration for service performed by an individual as a member of a uniformed service.

In the case of an individual performing service after December 31, 1956, as a member of a uniformed service (see section 31.3121(n)), to which the provisions of section 3121(m)(1) (see § 31.3121(m)) are applicable, the term “wages” shall, subject to the provisions of section 3121(a)(1) (see § 31.3121(a)-1), include as the individual's remuneration for such service only his basic pay as described in section 102(10) of the Servicemen's and Veterans' Survivor Benefits Act (38 U.S.C. 401(1), 403; 72 Stat. 1126).