In addition to improving the social security of working workers, international social security agreements help ensure continuity of benefit protection for people who have received social security credits under the U.S. system and another country. The provisions to eliminate dual coverage for workers are similar in all U.S. agreements. Each of them establishes a basic rule regarding the location of the employment of a workforce. Under this basic “territorial rule,” a worker who would otherwise be covered by both the United States and a foreign regime is subject exclusively to the coverage laws of the country in which he or she works. The following countries have signed a social security agreement with Quebec under which a pension application or a certificate of coverage can be applied for. Workers who are exempt from U.S. or foreign social security contributions under an agreement must document their exemption by obtaining a country coverage certificate that continues to cover it. For example, an American worker temporarily posted to the UK would need a SSA-issued coverage certificate to prove his exemption from UK social security contributions. Conversely, a UK-based employee working temporarily in the Us would need a certificate from the British authorities to prove the exemption from the US Social Security Tax.
Other features of U.S. law increase the likelihood that foreign workers in the United States will also face dual coverage. U.S. law provides mandatory social security for benefits paid as workers in the United States, regardless of the nationality or country of residence of the worker or employer, regardless of the length of residence of the worker in the United States. Unlike many other countries, the United States generally does not provide a guarantee exemption for non-resident foreign workers or workers who have been sent to work for a short period of time within their borders. This is why most foreign workers in the United States are covered by the U.S. program. The single-family home rule in U.S. agreements generally applies to workers whose interventions in the host country are expected to last 5 years or less. The 5-year limit for leave for exempt workers is much longer than the limit normally set by agreements in other countries. Any agreement (with the exception of the agreement with Italy) provides an exception to the territorial rule, which aims to minimize disruptions in the career of workers whose employers temporarily send abroad.
Under this “self-employed” exception, a person temporarily transferred to service for the same employer in another country is covered only by the country from which he or she was seconded.