Victor Gersten, EA, CFP®, MS, MPAS™
If you are paying into the Spanish system, are you also paying into the American one? That is one of the most common questions I get from Americans who have just moved to Spain.
The answer turns on a treaty from 1988 that most people have never heard of.
It is called a totalization agreement, and it does two useful things. It keeps you out of both social security systems at once. And it lets you combine your work history across the two countries when you claim a benefit. That second part is what gives the agreement its name.
For self-employed Americans in Spain, the first thing matters most. US self-employment tax runs at 15.3%, and the agreement can take it off the table entirely. That only works if you do the paperwork, which is where most people come unstuck.
Everything below is general information. It is not advice about your situation, and the tax sections depend on facts about your residency and your business that I do not know.
What the agreement is, and why it exists
The United States has social security agreements with roughly thirty countries. The one with Spain entered into force on 1 April 1988. The full text is published by the Social Security Administration at ssa.gov.
These agreements exist because the two countries use different tests. Spain generally charges social security based on where the work is performed. The US generally taxes its own citizens on self-employment income wherever they live.
Put those side by side without a treaty and the same euro gets picked up twice.
The agreement assigns each period of work to exactly one system. It then makes sure neither country’s vesting rules quietly strand you.
This is a coordination document, not a benefits document. It does not create new benefits or increase what either country pays.
The two problems it solves
Double contributions
Without the agreement, the same earnings could face Spanish social security and US self-employment tax, with no credit in either direction.
That is not a rounding error. Spanish contributions are substantial on their own. A US layer on top would be a second charge on money already taxed once for the same purpose.
Benefit gaps
The second problem is quieter and shows up decades later. Each system requires a minimum contribution history before it pays anything. A career split across two countries can leave you short in both.
Someone with eight years in the US and fifteen in Spain has a real working life behind them. Read under each country’s rules in isolation, that record could produce nothing from either system. The totalization provisions prevent that.
If a US employer sent you to Spain
The core rule for employees is in Article 5(1). It is usually called the detached worker rule.
If a US employer sends an employee to work temporarily in Spain, the employee stays covered by the US system. They do not switch to the Spanish one.
The word temporarily has a specific meaning. The article applies where the work is not expected to exceed five years. That is measured by the expectation at the outset, not by what happens later.
If circumstances stretch the assignment past that point, coverage may continue for a further period of not more than one year. That requires the consent of the other country’s competent authority. So the rule in force today is five years, extendable by one.
Read that extension slowly. The sixth year is not automatic, and the employee cannot elect it. It is a request the other country has to approve.
| Your situation | Which system generally covers you |
|---|---|
| Sent by a US employer, assignment under five years | United States |
| Hired locally by a Spanish employer | Spain |
| Self-employed and resident in Spain | Spain |
The middle row catches more people than the first. Took a job with a Spanish company? Or did your US employer move you onto a Spanish payroll or a local entity? Then you are almost certainly in the Spanish system. The detached worker rule is narrow, and it turns on the assignment rather than your passport.
If you are self-employed in Spain
Here the agreement earns its keep for a large share of my practice.
A US citizen who is self-employed, resident in Spain, covered by Spanish social security, and holding a certificate of coverage is exempt from US self-employment tax on that income. The SSA’s own pamphlet on the Spain agreement sets out the mechanism.
US self-employment tax funds Social Security and Medicare for people with no employer withholding. It is levied at 15.3%. It applies to US citizens wherever they live. And it is not reduced by the foreign earned income exclusion or by foreign tax credits. That surprises people who assumed the exclusion covered everything.
Here is a hypothetical illustration with round numbers. An American freelancer in Valencia with $60,000 of net self-employment income would face US self-employment tax of roughly $8,000 to $9,000 if no exemption applied. Covered by Spanish social security and holding a certificate, the agreement takes that income out of the US base. What any person actually owes depends on their facts and how the business is structured.
The exemption is not automatic. You do not claim it by leaving the income off the return. You claim it by filing and attaching documentation that references the agreement and the certificate. I would leave the exact mechanics to whoever prepares the return, because the presentation matters and it changes over time.
The certificate is the whole ballgame
The exemption depends on showing that Spain is covering you. Without a certificate of coverage in hand, you have a position you believe in and no document to support it. Request it when you register, not the week the return is due.
The autónomo side
On the Spanish side, a self-employed American registers as autónomo and pays the monthly cuota.
Spain moved the autónomo system to an income-based scale. So the amount owed is tied to declared earnings rather than a flat figure.
That matters for planning. Your contributions now move with your income, and the base you declare feeds into what Spain eventually pays you. The point of the agreement is not that you pay nothing. It is that you pay into one system rather than two.
The 2023 agreement: signed, not yet in force
A new social security agreement was signed on 8 April 2023. As of August 2026 it has not entered into force.
I want to be careful here. This is an area where confident claims have traveled further than the facts. The full text has not been published by the SSA, and the SSA’s list of agreements in force still shows Spain with the 1988 date only.
Entry into force follows a Congressional review period. Prior US totalization agreements have generally taken a couple of years from signature, though this one has run considerably longer.
Several law firm blogs say the new agreement extends the detached worker period from five years to seven. That figure circulates widely. I have found no primary source for it. Until the SSA publishes the text, nobody outside the negotiating rooms knows.
So my position is simple. Plan around the five-plus-one rule that is actually in force. If you are structuring an assignment on a seven-year assumption, you are relying on a number neither government has confirmed.
When the text is published, the conversation may change. Until then I would rather tell you what is not yet known than repeat a figure because it appeared in enough places to sound settled.
How to get a certificate of coverage
A certificate of coverage proves which system you belong to. The rule of thumb is simple. You request it from the system that covers you, not the one you are trying to stay out of.
If Spain covers you, it comes from the Tesorería General de la Seguridad Social. If the US covers you as a detached worker, it comes from the SSA.
I am not listing Spanish form numbers here. The TGSS procedure and its online routes change. Confirm the current steps with the TGSS or your gestor rather than following a stale instruction from an article.
The shape of the process does not change. An application to the covering authority, a certificate issued for a defined period, and a copy retained by you.
Two practical notes. Certificates expire, so an arrangement that runs long needs renewal. And keep the certificate with your tax records rather than in an email folder. It may be requested years later.
Combining credits across both countries
Totalization means adding periods together to reach a qualifying threshold. Short of coverage in one country? The agreement lets you count periods in the other toward that country’s minimum.
The US minimum for a retirement benefit is 40 credits, roughly ten years of covered work. Someone with seven years of US coverage and a long Spanish career can use the Spanish periods to get over the US line. The same logic runs the other way for Spanish benefits.
Here is the part people misunderstand. Combining credits qualifies you for a benefit. It does not enlarge either benefit beyond what your own contributions earned.
Each country then pays a partial benefit, calculated only on the periods you actually worked under that system. You are not paid twice for the same years. The Spanish periods that helped you qualify in the US do not increase the US payment.
Two partial benefits from two systems is the normal outcome. It beats one benefit and one forfeited record.
The WEP repeal
This is the piece that changed most recently, and it is good news for split careers.
The Social Security Fairness Act was signed on 5 January 2025. It repealed both the Windfall Elimination Provision and the Government Pension Offset. The SSA’s page is at ssa.gov.
WEP used to reduce a US Social Security benefit when the person also received a pension from work not covered by US Social Security. A Spanish pension is exactly that kind of pension. So an American with a split career could see the US benefit cut by a formula most people found impossible to follow.
That reduction is gone. Benefits are payable without the WEP or GPO reduction for months after December 2023, meaning January 2024 onward. The SSA began issuing retroactive payments in February 2025 and has reported that it substantially completed the retroactive processing during 2025.
Was your US benefit reduced by WEP before 2024? If you have not looked at your record since, that is worth checking. I will not tell you what the change is worth, because it depends on your earnings record. What I will say is that the reduction no longer applies, and the SSA has been adjusting records without requiring people to apply.
Three things to check this month
One. Do you hold a current certificate of coverage from whichever system covers you? Two. If you are self-employed, has the exemption been reflected on your US returns? Three. If WEP ever reduced your benefit, has the SSA updated your record?
Working with a cross-border adviser
Most of what goes wrong here is not a hard technical question. It is a coordination problem.
Registering the autónomo and handling the cuota sits on the Spanish side. Filing the 1040 and the foreign forms sits on the US side, and that is plenty of work on its own. The certificate of coverage sits between the two. That is exactly why it gets missed, and why the self-employment tax then gets paid year after year when it did not have to be.
That gap is where I work. Cross Border Wealth Advisors is a fee-only registered investment adviser, and I hold both the CFP® and the Enrolled Agent credential. The tax return and the financial plan get decided in one conversation rather than handed between two firms.
On this topic the work is concrete. Confirm which system covers you. Make sure a certificate exists and is current. Check that your US return claims the exemption correctly. Project both benefit streams so you see the combined picture. And review your record if WEP ever reduced your benefit.
None of that is exotic. It just has to be done by someone reading both rulebooks at once.
Living in Spain, or planning a move, and not certain which system you belong to? That conversation is better had before the next filing season. Book an introductory conversation at cbwealthadvisors.com or email info@cbwealthadvisors.com.
Everything above is general information, not advice about your circumstances. Your residency, your business structure and your work history in each country all change the answer.
Sources
- SSA, US-Spanish social security agreement, full text
- SSA, totalization agreement with Spain, pamphlet
- SSA, Social Security Fairness Act
Coordinating the two systems is one of several items to settle before you move. The full checklist is in Five Financial Mistakes Americans Make Before Moving to Spain.
Related reading: Retirement planning across two countries · Should You Keep Medicare While Living Abroad?
Disclosures
This article is general educational information published by Cross Border Wealth Advisors, a company of Gersten Financial Planning Inc., an investment adviser registered with the State of California (CRD 309890). It is not investment, tax, legal or immigration advice.
Rules and figures change. The ones here are stated as of the date above. Any calculation shown is a hypothetical illustration, not a projection and not any client’s experience. Cross Border Wealth Advisors is fee-only and receives no commissions. Registration does not imply a certain level of skill or training.
Please read the full article disclosures, which apply to everything published here.
