To determine whether U.S. insured status is met based on combined U.S. and foreign
coverage, the worker’s foreign coverage must be converted to quarterly increments
(if the foreign system does not credit on a quarterly basis) and allocated to his
or her U.S. earnings record. However, no credit may be given for any periods of foreign
coverage credited prior to January 1, 1937 or which coincide with a calendar quarter
that has already been credited as a U.S. quarter of coverage (QC).