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 the
worker's 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).