The agreement with Luxembourg became effective on November 1, 1993.

If both the U.S. and Luxembourg social security systems cover a worker's employment or self-employment, the agreement provides that beginning November 1, 1993, 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 November 1, 1993, those earnings remain subject to social security taxation in both countries.