A certificate of coverage certifies that SSA has determined that a worker's employment
or self- employment in an agreement country is covered by the U.S. system under terms
of the applicable agreement. Each certificate:
identifies the worker and his employer or the type of self-employment, and
shows the period for which it is valid.
Most certificates show both a beginning date and an ending date. Under some agreements
an ending date may not be shown; in such cases, the certificate is valid indefinately.