Only domestic lawyers (Austrian or EU/EEA/Swiss citizenship required), European lawyers (EU/EEA/Swiss citizenship required) or "internationally active lawyers" (citizenship of a GATS member state required) may be partners of a law firm. As of 2020, the shares and voting rights of internationally active lawyers in a law firm may not exceed a total of 25%. Previously, foreign investment in law firms [providing domestic law services only] by non-EU citizens was restricted to 49%. From 2020, a stricter 25% limit applies to law firms providing both domestic and international law services.
"Lawyers' Regulations
I. section - Requirements for practicing the legal profession
§ 1.
(1) To exercise the legal profession in (Note: now: Republic of Austria) no official appointment is required, only proof of fulfillment of the following requirements and entry in the list of lawyers. (§§ 5 and 5a)
[...]
(2) These requirements are:
a) (Note: now: Austrian citizenship) ;
[...]
(3) Citizenship of a member state of the European Union or another signatory state to the Agreement on the European Economic Area or the Swiss Confederation is equivalent to Austrian citizenship. [...]
[...]
§ 1a.
(1) The legal profession can also be practiced in a law firm in the legal form of a company under civil law, a registered partnership (legal partnership) or a corporation, with the exception of the legal form of a stock corporation. If the requirements of §§ 21a and 21c are complied with and the company concerned is effectively set up in accordance with the applicable law, the legal profession may also work in another member state of the European Union or another signatory state to the Agreement on the European Union Economic area or the Swiss Confederation for exercising the legal profession are exercised as a partnership or corporation, this with the exception of the legal form of a stock corporation (or a corporation of the same type). [...]
[...]
§ 21c. 
The following requirements must be met at all times for companies to practice law:
1. Partners may only be:
a) Domestic lawyers, lawyers within the meaning of the Annex to EIRAG [European lawyers] and internationally active lawyers under the conditions and to the extent of Section 41 (2) EIRAG [...]
G) Companies with limited liability as well as corporations of the same type within the meaning of Section 1a (1), second sentence, if they are the sole general partner of a legal partnership in the form of a limited partnership or a similar partnership within the meaning of Section 1a (1), second sentence.
[...]
11. Lawyers must have a majority in the company's capital and a decisive influence on the decision-making process. The exercise of the mandate by the lawyer belonging to the company may not be tied to instructions or the consent of the shareholders (shareholders' meeting).[...]" (Lawyers' Act (RGBl. Nr. 96/1868), last amended by BGBl. I No. 106/2021, §§ 1, 1a and 21c [google translation])
-----------------------
"§ 1.
(1) This Federal Act regulates in its 2nd, 3rd and 4th parts the exercise of the free movement of services and the establishment to exercise the legal profession in Austria by citizens of the member states of the European Union and the other contracting states of the Agreement on the European Economic Area as well as Swiss Confederation who are entitled to practice as a lawyer under one of the designations listed in the annex to this federal law (European lawyers).
[...]
(2) Part 5 of this Federal Act regulates the provision of legal services by lawyers who are citizens of a member state of the General Agreement on Trade in Services ( Federal Law Gazette No. 1/1995 ) and who belong to the professional organization of this member state and in are entitled to practice as a lawyer in this country (home country) (internationally active lawyers).
[...]
§ 41.[...]
(2) The admissibility as well as the possible extent of participation of an internationally active lawyer in a law firm entered in the list of law firms of a bar association are based on the obligations entered into by the Republic of Austria in international trade agreements or similar international agreements; the shares and voting rights of internationally active lawyers may not exceed a total of 25%. An extension of the substantive powers of the internationally active lawyer in Austria (§ 40) is not associated with such participation.[...]" (Act on the freedom to provide services and the establishment of European lawyers and the provision of legal services by internationally active lawyers in Austria (EIRAG; BGBl. I Nr. 27/2000), last amended by BGBl. I Nr. 157/2020, §§ 1 and 41 [google translation])
Lawyers' Act (RGBl. Nr. 96/1868), subsequently amended by BGBl. I No. 106/2021
Act on the freedom to provide services and the establishment of European lawyers and the provision of legal services by internationally active lawyers in Austria (EIRAG; BGBl. I Nr. 27/2000), last amended by BGBl. I Nr. 157/2020, §§ 1 and 41 
[<a href="https://www.ris.bka.gv.at/GeltendeFassung.wxe?Abfrage=Bundesnormen&Gesetzesnummer=10001673">Lawyers' Act</a>],[<a href="https://www.ris.bka.gv.at/GeltendeFassung.wxe?Abfrage=Bundesnormen&Gesetzesnummer=20000673">EIRAG</a>]