Under the agreement, a detached worker remains subject only to the social security
laws of the country from which he or she was sent, provided all of the following conditions are met:
The period of
employment in the host country is expected to last no more than 5 years. The 5-year period is
considered to begin with the date the employment in the host country begins or the
effective date of the agreement (August 1, 1989), whichever is later.
The employment relationship must exist before the employee is transferred from the home country.
In the case of an employee who is sent by an American employer to become the employee of the company's affiliate
in Portugal, the American employer must have entered into an agreement under Section 3121(l)
of the Internal Revenue Code with respect to the affiliate.
NOTE: The detached worker rule applies even if an employee has not been sent directly from
one country to the other but is first assigned to work in a third country.