Chile pioneered fully-funded individual pension accounts: workers pay about 10% of salary into a personal AFP account they own outright, rather than into a pay-as-you-go pool. The agreement prevents double coverage with U.S. FICA and coordinates benefit eligibility with the legacy public system.
U.S. retirement benefits normally need 40 quarters (10 years) of credits. If you split a career between the U.S. and Chile, you might fall short in each country alone. As long as you have at least 6 quarters of U.S. credits, the agreement lets you add your Chile credits to reach eligibility — the U.S. then pays a benefit pro-rated to your U.S. credits only.
A Certificate of Coverage is the document that proves you're exempt from one country's social security. For U.S. coverage, the employer requests it from the SSA Office of Earnings & International Operations. Chile's authority issues the equivalent when Chile covers you.
Under the U.S.–Chile agreement, a worker sent by a U.S. employer for 5 years or less normally stays under U.S. Social Security only and is exempt from Chile's system. Your employer obtains a U.S. Certificate of Coverage as proof. Beyond 5 years, coverage shifts to Chile.
Yes. If you have at least 6 quarters (about 1.5 years) of U.S. credits, the agreement lets you combine ("totalize") your U.S. and Chile credits to reach the 40-quarter (10-year) threshold for a pro-rated U.S. retirement benefit.
The agreement has been in force since 2001.
Pension taxation depends on Chile's domestic law and the separate U.S.–Chile income tax treaty (if any), not the totalization agreement. The totalization agreement only governs which country's social security system covers you and how credits combine. Confirm pension taxation with a cross-border tax advisor.
It remains your property, keeps its investment returns, and pays out under Chilean rules at retirement (with limited early-withdrawal cases for foreign technical workers). Unlike pay-as-you-go systems, no totalization is needed to preserve it — though the agreement still governs which country you contribute to while working.