Gustaaf specializes in corporate and M&A, and competition / antitrust, advising clients across a broad range of industries, including automotive, aviation, consumer goods & e-commerce, education, financial institutions, pharmaceuticals & healthcare, power & renewables, real estate & infrastructure, shipping & maritime, telecoms, and tourism. He is also involved in arbitration work.

In his corporate and M&A practice, Gustaaf has assisted a long list of high-end multinational clients with their M&A and FDI deals in Indonesia, the Indonesian aspects of global M&A deals, and the drafting of transaction documents, such as share purchase agreements, share subscription agreements, asset purchase agreements, shareholders agreements and related commercial agreements. He also regularly advises on the establishment of joint-venture companies in Indonesia and the negotiating and drafting of joint-venture agreements. 

In competition / antitrust, Gustaaf focuses on cartel, dominant-position, and merger-control matters, and has worked on several landmark merger-control cases in Indonesia. In addition, he regularly reviews commercial agreements from an antitrust perspective and has been involved in corporate internal investigations relating to antitrust issues for a range of multinational clients with operations in Indonesia. He also regularly assists international and regional law firms with the Indonesian competition law aspects of global and foreign-to-foreign deals.

As a key member of ABNR’s award-winning aviation practice, Gustaaf advises across the entire industry spectrum (airside and groundside), including aircraft and aircraft-engine financing, acquisition, and leasing (wet and dry), comprising secured lending (Cape Town Convention), operating and finance leasing, and syndicated financing. He also regularly handles the Indonesian aspects of aviation matters on behalf of leading international law firms.

Benefiting from his knowledge of Dutch contract law (on which Indonesian contract law is based), and building on over 10 years of experience in FDI, M&A and commercial transactions in Indonesia, Gustaaf also has a developing arbitration practice. He advises corporate clients and foreign law firms involved in Indonesian law-related arbitration proceedings on critical contract law concepts and related case law and doctrinal interpretations. Gustaaf also assists clients with the enforcement of foreign arbitral awards in Indonesia. He is a Fellow of the Chartered Institute of Arbitrators (FCIArb), making him one of only a handful of foreign lawyers active in Indonesia with this qualification.

Prior to joining ABNR, Gustaaf worked as an associate in the Amsterdam and Brussels offices of a Netherlands-based tier-1 law firm. 

Gustaaf is a graduate of Leiden University in the Netherlands, where he earned an LL.M in private law, an MA in Indonesian studies, and a PhD for a dissertation on Indonesian land law. In addition, he read law at King’s College and The School of Oriental and African Studies in London, England, and studied French at the University of Burgundy in Dijon, France. 

Gustaaf regularly publishes articles and makes presentations on Indonesian legal matters, and serves as a guest lecturer at several Indonesian universities, as well as the Indonesian Ministry of Law and Human Rights. He was admitted to the Amsterdam Bar in 2008 and is a registered foreign lawyer in Indonesia. He also serves as Legal Secretary and Executive Board member of the EU-ASEAN Business Council (EU-ABC) in Singapore, Executive Board representative of the European Chamber of Commerce (EuroCham), and member of the Board of Trustees of the Dutch Business Network (DBN) in Indonesia.

Gustaaf is the only lawyer in Indonesia to be ranked in the spotlight table as a foreign legal consultant for Competition/Antitrust by Chambers Asia Pacific. He is also recognized as a “Leading Individual” for Competition and Antitrust, and recommended for Corporate and M&A, Aviation and Real Estate, by The Legal 500 Asia Pacific.

Client testimonials

From Chambers Asia Pacific, 2024 ed.:

"Gustaaf is a very skilled lawyer and his knowledge of several competition law systems can be of great value to navigate clients through a sometimes challenging process."

"He is always prompt in responding to our enquiries and provides practical solutions to our concerns, rather than simply citing the regulations and precedents."

From Chambers Asia Pacific, 2023 ed.:

‘Even though he is a high-level partner, he is always ready to provide advice himself with support from locally qualified partners.’

‘He has been able to solve several issues we have faced in the filing process.’

From The Legal 500 Asia Pacific, 2023 ed.:

‘Gustaaf Reerink has a good understanding of the global merger control process and ability to take this into account for the Indonesian process. Smooth handling of filing preparation and notification process.’

‘The team is led by Gustaaf Reerink, who has a top-tier global competition law practice. He strongly leads the team with global standard and at the same time, maintain the strength as a local law firm, where each of the lawyers can effectively communicate with the competition law authority (KPPU).’

From The Legal 500 Asia Pacific, 2022 ed.:

‘Gustaaf Reerink is an excellent competition law lawyer.’

‘Gustaaf Reerink is very prompt and clear in his advice. He understands the client’s needs and effectively guides us to pre-empt any issues for our antitrust matters in Indonesia.’

Regulatory notice: Mr. Reerink’s practice does not include the administration of escrow funds.





  • Chambers 2024 Competition/Antitrust: Foreign Legal Consultants Chambers 2024 Competition/Antitrust: Foreign Legal Consultants
  • Legal 500 Asia Pacific Leading Individual Legal 500 Asia Pacific Leading Individual
  • Legal 500 Asia Pacific Recommended Lawyers Legal 500 Asia Pacific Recommended Lawyers