If both the U.S. and Australian social security systems cover a worker’s employment
or self-employment, the Agreement provides that beginning October 1, 2002, only one
country’s system will cover the worker’s employment or self-employment. The Agreement
does not affect a worker's coverage prior to that date. If a worker had dually-covered
earnings before October 1, 2002, that were dually covered, those earnings remain subject
to social security taxation in both countries.