Judgment — ECLI:EU:C:2024:802
Date: 2024-09-26
Language of the case: German
Court formation: Seventh Chamber
Subject matter: Social security for migrant workers;Free movement of workers
Procedure: Reference for a preliminary ruling
Origin: Austria

Summary C-329/23 – 1 
Case C-329/23 
Summary of the request for a preliminary ruling pursuant to Article 98(1) of 
the Rules of Procedure of the Court of Justice 
Date lodged: 
25 May 2023 
Referring court: 
Verwaltungsgerichtshof (Austria) 
Date of the decision to refer: 
9 May 2023 
Appellant on a point of law: 
Sozialversicherungsanstalt der Selbständigen 
Interested party: 
Dr. W M 
  
Subject matter of the main proceedings  
Social security legislation – Self-employment in a Member State, an EEA state 
and a third state – Coordination rules – Jurisdiction 
Subject matter and legal basis of the reference 
Interpretation of EU law, Article 267 TFEU 
Questions for a preliminary ruling 
1. Are the rules of EU law on the determination of the applicable legislation in 
the area of social security according to Regulation (EC) No 883/2004 in 
conjunction with Regulation (EC) No 987/2009 to be applied to a situation in 
which an EU citizen is simultaneously self-employed in an EU State, an EEA 
EFTA State (Liechtenstein) and Switzerland. 
If the answer to the first question is in the affirmative: 
EN 
SUMMARY OF THE REQUEST FOR A PRELIMINARY RULING – CASE C-329/23 
 
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2. Must the application of Regulation (EC) No 883/2004 in conjunction with 
Regulation (EC) No 987/2009 in such a case be such that the applicability of the 
social security legislation must be assessed separately in the relationship between 
the EU Member State and the EEA-EFTA State, on the one hand, and the 
relationship between the EU Member State and Switzerland, on the other hand, 
and must, accordingly, a separate certificate regarding the applicable legislation be 
issued in each case? 
3. Is there a change in the ‘relevant situation’ within the meaning of 
Article 87(8) of Regulation, (EC) No 883/2004 where a self-employment activity 
is commenced in another State to which the said regulation is applicable, even if a 
change in the applicable legislation would not result either under Regulation (EC) 
No 883/2004 or under Regulation (EEC) No 1408/71 and the activity is so 
subordinate in extent that only about 3% of total income is thereby obtained? 
Does it make any difference whether, within the meaning of the second question, 
the coordination in the bilateral relationship between the States previously 
concerned, on the one hand, and between one of the States previously concerned 
and the ‘other State’, on the other hand, must be conducted separately? 
Provisions of EU law relied on 
Regulation (EC) No 883/2004 of the European Parliament and of the Council of 
29 April 2004 on the coordination of social security systems 
Regulation (EC) No 987/2009 of the European Parliament and of the Council of 
16 September 2009 laying down the procedure for implementing Regulation (EC) 
No 883/2004 on the coordination of social security systems 
Council Regulation (EEC) No 1408/71 of 14 June 1971 on the application of 
social security schemes to employed persons and their families moving within the 
Community 
Succinct presentation of the facts and procedure in the main proceedings  
1 The interested party is an Austrian and Liechtenstein national, lives in Austria 
and, in the period at issue in this case (1.1.2017 to 31.3.2018), worked as a self-
employed doctor in Austria, Liechtenstein and Switzerland. He obtained about 
19% of his income in Austria, 78% in Liechtenstein and 3% in Switzerland. He 
commenced his activity in Switzerland on 1.1.2017. He was previously clearly 
subject to Austrian social security legislation on the basis of his residence in 
Austria pursuant to Article 14a(2) of Regulation (EEC) No 1408/71. 
2 On 14 April 2020, the interested party applied for an E 101 form from the 
appellant, the Sozialversicherungsanstalt (Social Security Institution), pursuant to 
SOZIALVERSICHERUNGSANSTALT 
 
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Regulation (EEC) No 1408/71, for the period 1.1.2017 to 31.3.2018, from which it 
is apparent that Austrian social security legislation applies to the applicant. 
3 The Sozialversicherungsanstalt interpreted the application as an application for an 
A1 form under Regulation (EC) No 883/2004 in conjunction with Regulation 
(EC) No 987/2009 and rejected it by decision of 21 October on the ground that, 
although Regulation (EC) No 883/2004 in conjunction with Regulation (EC) 
No 987/2009 (or, under the transitional provision in Article 87 of Regulation [EC] 
No 883/2004, Regulation (EEC) No1408/71) applied in relation to Liechtenstein 
under the EEA Agreement and Regulation (EC) No 883/2004 in conjunction with 
Regulation (EC) No 987/2009 similarly applied in relation to Switzerland under 
the Agreement on the Free Movement of Persons between the EU and 
Switzerland, there was no umbrella agreement providing for comprehensive 
coordination at European level collectively covering the EU States, the EEA-
EFTA States and Switzerland. The activities of the interested party in the relevant 
period were therefore separately subject to the legislations of Austria, 
Liechtenstein and Switzerland. 
4 The interested party lodged an appeal against that decision, which the 
Bundesverwaltungsgericht (Federal Administrative Court) upheld by decision of 
28 January 2022. It ruled that the interested party had to be issued with an E 101 
or A 1 form certifying that those activities were subject to Austrian social security 
legislation, both for his activity in Liechtenstein and for his activity in Switzerland 
in the period at issue in this case. 
5 According to the Bundesverwaltungsgericht, it is, first of all, clear that the 
interested party was subject to Austrian social security legislation; however, his 
commencement of activity in Switzerland raises the issue whether the hitherto 
decisive provisions of Regulation (EEC) No 1408/71 are still applicable. 
However, in its view, there is no need for a separate umbrella agreement. The 
‘Austria-Liechtenstein self-employment’ situation must be assessed on the basis 
of the EEA Agreement and the Agreement on the Free Movement of Persons 
applies to the ‘Austria-Switzerland self-employment’ situation. 
6 In the present case, Regulation (EC) No 883/2004 is applicable under the EEA 
Agreement and, pursuant to the transitional provisions of that regulation, the 
interested party has so far been subject to Regulation (EEC) No 1408/71 in respect 
of his parallel self-employment in Austria and Liechtenstein. The commencement 
of his activity in Switzerland is not covered by the EEA Agreement and does not 
result in any change in the situation within the meaning of Article 87(8) of 
Regulation (EC) No 883/2004. The interested party must therefore Ibe issued, as 
before, with an E 101 certificate in respect of his parallel employment in Austria 
and Liechtenstein certifying that he is subject to compulsory social insurance in 
Austria. 
7 The parallel self-employment in the Austria-Switzerland relationship must be 
assessed on the basis of the Agreement on the Free Movement of Persons in 
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accordance with Regulation (EC) No 883/2004. Since the self-employment 
activity occurred mainly in Austria (the Member State of residence), the self-
employment activity in Switzerland is also subject to compulsory social insurance 
in Austria. 
8 The Sozialversicherungsanstalt brought an appeal on a point of law before the 
Verwaltungsgerichtshof (Supreme Administrative Court) against that decision. It 
submitted that the question arises how Regulation (EC) No 883/2004, Regulation 
(EC) No 987/2009 and Regulation (EEC) No 1408/71 interact in the present case. 
It maintains that the assessment of the Bundesverwaltungsgericht is incorrect, 
since the EU legislation is not applicable in relation to the three States involved. 
The interested party’s activities are instead separately subject to the legislations of 
Austria, Liechtenstein and Switzerland. 
9 The interested party contended that the Bundesverwaltungsgericht’s decision is 
ultimately correct, that, however, the situation does not need to be divided into an 
Austria-Liechtenstein relationship and an Austria-Switzerland relationship. In its 
view, whether Austrian or Liechtenstein social security legislation is applicable is 
relevant only in the relationship between the Austrian social security institution 
and the Liechtenstein authorities. There is no need for an umbrella agreement and 
it is also not apparent why, without such an agreement, Regulation (EC) 
No 883/2004 should not be applicable. The matter relates to the EEA Agreement 
together with its annexes and thereby Regulation (EC) No 883/2004, which results 
in the applicability of Regulation (EEC) No 1408/71. 
10 He also submitted that it is not a typical third State situation, since both of the 
aforementioned regulations also apply in relation to Liechtenstein and 
Switzerland, in the latter case, under the Free Movement of Persons Agreement. It 
would be paradoxical if mandatorily applicable EU legislation were circumvented 
by the bilateral Switzerland-Liechtenstein relationship in Austria. The application 
of Regulation (EC) No 883/2004 also does not depend on the existence of an 
umbrella agreement. Since the relevant situation remains unchanged by his 
activity in Switzerland (amounting to 3% of income), his self-employment activity 
remains subject to compulsory social insurance in Austria. 
Succinct presentation of the reasoning in the reference for a preliminary 
ruling  
11 In the case of the EU Member States, the matter of which social security 
regulations apply to a citizen who is self-employed in more than one State is 
provided for under Regulation (EC) No 883/2004 in conjunction with Regulation 
(EC) No 987/2009. That coordination of EU legislation was declared to be 
applicable also in the relationship with other States by means of agreements such 
as the EEA Agreement or the Agreement on Free Movement of Persons between 
the EU and Switzerland. Neither of those two agreements contains a basis for 
including third-country nationals in the coordination, nor is there any provision 
SOZIALVERSICHERUNGSANSTALT 
 
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regarding the coordination in respect of any other agreement or any overarching 
agreement covering both the EEA States and Switzerland. 
Questions 1 and 2 
12 Since such an overarching agreement does not exist, the 
Bundesverwaltungsgericht concludes that the EEA Agreement and the Agreement 
on Free Movement of Persons must be considered separately and that two separate 
certificates regarding the applicable social security provisions must be issued, one 
in respect of the Austria-Liechtenstein relationship and the other in respect of the 
Austria-Switzerland relationship. 
13 The interested party considers that the Austria-Liechtenstein relationship must 
likewise be assessed separately, whereas the Austria-Switzerland relationship does 
not need to be decided in this case. 
14 The Sozialversicherungsanstalt considers that there is absolutely no need for 
coordination under Regulation (EC) No 883/2004 in conjunction with Regulation 
(EC) No 987/2009 in this case. 
15 The procedure of the Bundesverwaltungsgericht does not appear to be compatible 
with the aim of coordination law to provide for a single legal system applicable to 
each person in a specific period of time. That principle of a single system also 
means that the establishment of applicable regulations under coordination law is 
not activity-related, but person-related. Issuing two different E 101 or A1 
certificates for the same person and the same period is accordingly precluded from 
the outset. 
16 In this case, the Bundesverwaltungsgericht’s two separate assessments resulted in 
the applicability of Austrian regulations only by chance. A slightly altered 
situation might result, in the case of separate assessment only of the bilateral 
relationships, in the legislation of different States being simultaneously applicable. 
The interested party’s approach would also ultimately have the same result. As 
soon as a dispute arose about the provisions applicable in relation to Switzerland, 
a decision would have to be made which might conflict with the establishment of 
the regulations applicable in relation to Liechtenstein. 
17 Such an outcome can be avoided only if it were to be concluded from the 
applicability of the EU coordination legislation under the EEA Agreement and the 
Agreement on Free Movement of Persons with Switzerland that, in a trilateral 
case such as that in the present proceedings, the coordination must be conducted 
jointly among all States and not separately in relation to the respective bilateral 
situations. In the absence of an overarching agreement, there is apparently, 
however, no legal basis for that. 
18 The referring court considers that, for those reasons, the EU law coordination 
rules cannot be applied directly or indirectly in this case. However, that does not 
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mean that the applicability of the coordination legislation in the Austria-
Liechtenstein relationship is circumvented by the agreement with Switzerland, 
since that agreement contains no provisions opposing the applicability of 
Regulation (EC) No 883/2004. Its inapplicability stems rather from the fact that 
neither the regulation nor the agreement provides for a trilateral situation and that 
a separate assessment by respectively applying that regulation to bilateral 
situations is contrary to the principle that a single social security system should 
apply. 
19 Since the referring court’s interpretation is not so clear as to leave no reasonable 
room for doubt, the first two questions had to be referred for a preliminary ruling. 
Question 3 
20 Should Regulation (EC) No 883/2004 be applicable to the present case, the 
question arises how the transitional provision in Article 87(8) is to be interpreted. 
21 Until he commenced his self-employment activity in Switzerland, the interested 
party was clearly subject to Austrian social security legislation on the basis of his 
residence in Austria pursuant to Article 14a(2) of Regulation (EEC) No 1408/71. 
Regulation (EC) No 883/2004 contains no comparable provision. Under 
Article 13(2) thereof, the legislation of the Member State of residence applies 
instead to self-employment in more than one Member State only if a substantial 
part of the self-employment activity is pursued there; otherwise, the legislation of 
the Member State in which the centre of interest of the activity is situated applies. 
In the present case, that provision would actually result in the applicability of the 
Liechtenstein social security legislation, although the Austrian legislation was 
initially still applicable on the basis of the transitional provision in Article 87(8) of 
Regulation (EC) No 883/2004. The commencement of an additional self-
employment activity accounting for 3% of total income in another State subject to 
the coordination legislation could not have resulted, within the scope of 
application of Regulation (EEC) No 1408/71, in a different jurisdiction, since, 
under Article 14a(2) thereof, it is only the State of residence which is decisive, as 
long as a part of the activity is pursued there. Within the scope of application of 
Regulation (EC) No 883/2004, a self-employment activity on such a small scale 
likewise does not alter the applicability of the legislation of the Member State of 
residence in which a substantial part of the activity is pursued. 
22 In those circumstances, a change in the ‘relevant situation’ within the meaning of 
Article 87(8) of Regulation (EC) No 883/2004 might be ruled out where only 
minor self-employment activity in another State subject to the coordination 
legislation (which is not the State of residence) is added to self-employment 
activities which have already been pursued, since that is irrelevant to the 
determination of the applicable legislation both under Regulation (EC) 
No 883/2004 and under Regulation (EEC) No 1408/71. 
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23 However, it might also be argued that further self-employment activity in another 
State subject to the coordination legislation implies a change in the relevant 
situation in any event, since a further State must now be included in the 
coordination, even where this would not result in any change in jurisdiction. If one 
were to take that view, the question arises, however, whether activity on such a 
small scale also causes a change in the relevant situation in this case. 
24 If the applicability of the social security legislation in the relationship between 
two EEA States were to be assessed independently of the situation existing in 
relation to Switzerland, the commencement of a self-employment activity in 
Switzerland should, at the outset, have no bearing on the assessment of the 
relationship of the EEA States. Therefore, the referring court’s view (which in that 
regard coincides with that of the Bundesgerictshof) is that the activity in 
Switzerland also cannot cause a change in the relevant situation within the 
meaning of Article 87(8) of Regulation (EC) No 883/2004. 
25 Since the answers to that question and the supplementary question also do not 
appear to be sufficiently clear, they had to be referred to the Court of Justice for a 
preliminary ruling.