DUTCH U.S. SOCIAL SECURITY TAX TREATY (link to text)
According to this agreement, you are either insured for social security in the Netherlands or in the United States. However, it's not possible to be insured in both countries at the same time.
As a basic rule, anyone who lives and works in The Netherlands is subject to social security legislation in The Netherlands. Consequently, you will be exempt from U.S. Social Security obligations.
This is even the case if your employer is based in the U.S. and you are paid from the U.S. However, an exemption can be claimed in the case of a short term assignment to the Netherlands and you and your employer choose to keep you covered under the U.S. Social Security System. In order to get this exemption, you have to request a statement from the U.S. Social Security Administration stating that you are in fact subject to the U.S. Social Security System. This is called a Certificate of Coverage.
If you are a self-employed American citizen living in the Netherlands and are subject to social security legislation in the Netherlands, you will therefore be exempt from U.S. self-employment tax under the U.S. / Netherlands Social Security Agreement.
See below for a simple explanation of where employees are covered for social security according to the U.S./Netherlands Social Security Agreement (also known as Totalization Agreement):
You are working in the Netherlands:
Your work status
Coverage and taxes
For U.S. employer who sent you to work in the Netherlands for five years or less
For U.S. employer who sent you to work in the Netherlands for more than five years
For U.S. employer who hired you in the Netherlands
For non-U.S. employer
For the U.S. government and you are a U.S. national
U.S. (either Social Security or federal retirement program)
For the U.S. government and you are a Dutch national
You are working in the U.S.
For an employer in the Netherlands who sent you to work in the U.S. for five years or less
For an employer in the Netherlands who sent you to work in the U.S. for more than five years
For an employer in the Netherlands who hired you in the U.S.
For a non-Dutch employer
For the Dutch government and you are a Dutch national
For the Dutch government and you are a U.S. national
You are self-employed and you:
Reside in the U.S.
Reside in the Netherlands