Foreign investment in commercial mediation/arbitration services is subject to a joint venture with Vietnamese partners, i.e. an arbitration centre is required to have at least five founders who are Vietnamese citizens and legally eligible to act as arbitrators.
"Article 3. Definitions
For the purposes of this Law, the terms below are construed as follows: [...]
10. “market access conditions applied to foreign investors” mean those which must be satisfied by foreign investors to make investment in the List of business lines with prohibited and restricted market access (hereinafter referred to as “the Negative List for Market Access”) specified in Clause 2 Article 9 of this Law.  [...]
19. “foreign investor” means an individual holding a foreign nationality or an organization established under foreign laws and carrying our business investment activities in Vietnam.
20. “domestic investor” means an individual holding Vietnamese nationality or a business organization whose members or shareholders are not foreign investors. 
[...]
Article 4. Application of the Law on Investment and relevant laws
1. Business investment activities in the territory of Vietnam [must] comply with the Law on investment [this Law] and other relevant laws.
2. If there is any discrepancy between the provisions of this Law and those of another law issued before the effective date of this Law in relation to the industries and trades in which business investment is prohibited, or industries and trades in which business investment is conditional, then the provisions of the Law on investment [this Law] shall prevail.
[...]
Article 9. Business lines with prohibited and restricted market access and market access conditions applied to foreign investors
1. Market access conditions applied to foreign investors are the same as those applied to domestic investors, except for the case specified in Clause 2 of this Article.
2. Pursuant to Laws and Resolutions of the National Assembly, Ordinances and Resolutions of the Standing Committee of the National Assembly, Decrees of the Government and international treaties to which the Socialist Republic of Vietnam is a signatory, the Government shall promulgate a Negative List for Market Access, including:
a/ Prohibited business lines; b/ Restricted business lines.
3. Market access conditions applied to foreign investors specified in the Negative List for Market Access include:
a/ Holding of charter capital by the foreign investor in a business organization; b/ Investment method; c/ Scope of investment; d/ Capacity of the investor; partners participating in the investment activities; dd) Other conditions specified in the Laws and Resolutions of the National Assembly, Ordinances and Resolutions of the Standing Committee of the National Assembly, Decrees of the Government and international treaties to which the Socialist Republic of Vietnam is a signatory.
[...]
Article 23. Implementation of investment activities by foreign-invested economic organizations
1. When making investment in establishment of other economic organizations; contribution of capital to, or purchase of shares or capital contributions at, other economic organizations; or investment in the form of BCC, economic organizations must meet the conditions and shall carry out investment procedures according to regulations applicable to foreign investors if falling into one of the following cases:
a/ Having over 50% of their charter capital held by a foreign investor/foreign investors, or having a majority of their general partners being foreign individuals, for partnerships;
b/ Having over 50% of their charter capital held by an economic organization/economic organizations specified at Point a of this Clause;
c/ Having over 50% of their charter capital held by a foreign investor/foreign investors and an economic organization/economic organizations specified at Point a of this Clause. [...]" (Law on Investment No. 61/2020/QH14 of 17 June 2020 [google translation])
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"Section 2. SECTORS, LINES AND MARKET ACCESS CONDITIONS FOR FOREIGN INVESTORS
Article 15. Sectors and trades restricted from market access for foreign investors
1. Sectors and trades with restrictions on market access for foreign investors and restrictions on market access for such industries and trades are prescribed in laws and resolutions of the National Assembly, ordinances and resolutions. of the National Assembly Standing Committee, Government decrees and international treaties on investment. The list of industries and trades with restrictions on market access for foreign investors is published in Appendix I of this Decree.
2. Market access conditions for foreign investors shall be applied in the forms specified in Clause 3, Article 9 of the Law on Investment and posted and updated according to the provisions of Article 18 of this Decree.
[...]
Article 16. Subjects of application of the List of industries and trades restricted from market access
1. The list of industries and trades with restricted market access applies to:
a) Foreign investors as prescribed in Clause 19, Article 3 of the Law on Investment ;
b) The economic organization specified at Points a, b and c, Clause 1, Article 23 of the Law on Investment when investing in the establishment of other economic organizations; make capital contribution, purchase shares, purchase capital contribution portion of other economic organizations; investment in the form of BCC contract.
(In this Section, the subjects specified at Points a and b of this Clause, hereinafter collectively referred to as foreign investors, unless otherwise provided for by this Decree).
[...]
Article 17. Principles of applying restrictions on market access for foreign investors
1. Except for the industries and trades on the List of industries and trades with restricted market access for foreign investors specified in Appendix I of this Decree, foreign investors are entitled to market access as prescribed for domestic investors.
2. Foreign investors are not allowed to invest in industries and trades that have not yet been able to access the market as prescribed in Section A, Appendix I of this Decree.
3. For industries and trades with conditional market access for foreign investors as prescribed in Section B, Appendix I of this Decree, foreign investors must satisfy the conditions for market access according to the provisions of Article 18 of this Decree.
4. Market access conditions for industries and trades that Vietnam has not yet committed to market access to for foreign investors are applied as follows:
a) Where laws and resolutions of the National Assembly, ordinances and resolutions of the National Assembly Standing Committee, decrees of the Government (hereinafter referred to as Vietnamese law) do not contain provisions restricting access to the market for that industry or trade, foreign investors may access the market as prescribed for domestic investors;
b) Where Vietnamese law already contains provisions on restricting foreign investors' market access for such industries or trades, the provisions of Vietnamese law shall apply. [...]
7. Foreign investors belonging to countries or territories that are not members of the WTO and conducting investment activities in Vietnam are entitled to the same market access conditions as those applicable to national investors. a territory that is a member of the WTO, unless otherwise provided for by Vietnamese law or an international treaty between Vietnam and that country or territory.
[...]
B. BUSINESS LINES WITH RESTRICTED MARKET ACCESS [...]
41. Commercial Arbitration Services, Arbitration Mediation [...]"(Government Decree on the Elaboration of Some Articles of the Law on Investment No. 31/2021/ND-CP of 26 March 2021 [google translation] (Decree 31), which provides guidance on the implementation of the new Law on Investment [google translation])
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"INDUSTRY, SECTOR | CONDITIONS LIMITED MARKET ACCESS | LEGAL BASIS [not reproduced here] [...]
41. Commercial Arbitration Services, Arbitration Mediation (CPC 86602)
1. Provisions in Agreements: Not limited to Arbitration and Conciliation Services (CPC 86602), except for arbitration and mediation services for commercial disputes between businesses.
The head of branch must be a resident of Vietnam In addition, under the CPTPP, Vietnam reserves the right to adopt and maintain any measure related to these sub-sectors.
2. Vietnamese law:
The foreign commercial mediation organization operates in Vietnam in the following forms: a) The branch of the foreign commercial mediation organization (hereinafter referred to as the branch); b) Representative office of a foreign commercial mediation organization (hereinafter referred to as representative office).
An arbitration center is established when there are at least five founders who are Vietnamese citizens who are eligible to act as arbitrators specified in Article 20 of the Law on Commercial Arbitration and was granted an establishment license by the Minister of Justice [...]" (Government of Viet Nam, List B: List of occupations with conditional market access for foreign investors: Conditions (updated 2020), webpage [google translation])
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"Chapter IV - COMMERCIAL MEDIATION INSTITUTIONS
Article 18. Commercial mediation institutions
Commercial mediation institutions include:
1. Commercial mediation centers that are established and operate in accordance with this Decree.
2. Arbitration centers that are established and operate in accordance with the law on commercial arbitration and carry out commercial mediation activities under Article 23 of this Decree.
[...]
Article 21. Procedures for establishment of commercial mediation centers
1. A Vietnamese citizen who fully satisfies the criteria for a commercial mediator specified in Clause 1, Article 7 of this Decree and wishes to establish a commercial mediation center shall send 1 set of dossier to the Ministry of Justice, comprising: 
[...]
Chapter V - OPERATION OF VIETNAM-BASED FOREIGN COMMERCIAL MEDIATION INSTITUTIONS
Article 33. Conditions for and forms of operation of Vietnam-based foreign commercial mediation institutions
1. Foreign commercial mediation institutions that are lawfully established and operate in foreign countries and respect the Constitution and laws of the Socialist Republic of Vietnam may operate in Vietnam in accordance with this Decree.
2. Foreign commercial mediation institutions may operate in Vietnam in the following forms:
a/ Branches of foreign commercial mediation institutions (below referred to as branches);
b/ Representative offices of foreign commercial mediation institutions (below referred to as representative offices).
Article 34. Branches and representative offices of Vietnam-based foreign commercial mediation institutions
1. Branch is a dependent unit of a foreign commercial mediation institution, which is established to carry out commercial mediation activities in Vietnam in accordance with this Decree. A foreign commercial mediation institution shall take responsibility before Vietnamese law for the operation of its branch. The foreign commercial mediation institution shall appoint a commercial mediator to be head of its branch. The head of a branch shall act as the authorized representative of a Vietnam-based foreign commercial mediation institution.
[...]
Article 36. Grant of licenses for establishment of branches or representative offices of Vietnam-based foreign commercial mediation institutions
1. A foreign commercial mediation institution that wishes to establish a branch or representative office in Vietnam shall send 1 set of dossier to the Ministry of Justice, comprising:
a/ A written request for establishment of a branch or representative office, made according to a form issued by the Ministry of Justice;
b/ A certified copy of the paper proving the lawful establishment of the institution, issued by a competent foreign authority;
c/ A written introduction of the institution’s operation;
d/ The decision appointing a commercial mediator to be the head of the branch or representative office;
dd/ A list of commercial mediators and staff members expected to work at the branch; or a list of staff members expected to work at the representative office. [...]" (Decree No. 22/2017/ND-CP dated February 24, 2017 of the Government on commercial mediation [google translation])
Law on Investment No. 61/2020/QH14 of 17 June 2020 [google translation]
Government Decree on the Elaboration of Some Articles of the Law on Investment No. 31/2021/ND-CP of 26 March 2021 [google translation]
Government of Viet Nam, List B: List of occupations with conditional market access for foreign investors: Conditions (updated 2020), webpage [google translation]
Decree No. 22/2017/ND-CP dated February 24, 2017 of the Government on commercial mediation [google translation]
[<a href="https://vbpl.vn/bokehoachvadautu/Pages/vbpqen-toanvan.aspx?dvid=312&ItemID=11133">Law</a>],[<a href="https://vbpl.vn/bokehoachvadautu/Pages/vbpq-toanvan.aspx?ItemID=147720&Keyword=31/2021/ND-CP">Decree</a>],[<a href="https://vietnaminvest.gov.vn/SitePages/News_Detail.aspx?ChuyenMuc=3&ItemId=16">Webpage</a>],[<a href="https://vbpl.vn/TW/Pages/vbpq-toanvan.aspx?ItemID=26117">Decree</a>]