Our People

IDSP Partner

Indra Siallagan

Indra Siallagan is the Founder and Managing Partner of IDSP, with over 25 years of experience in the tax sector, spanning both his formative years at the Indonesian Tax Authority and his role as a trusted advisor to multinational and local companies.

As a graduate from the Indonesia State College of Accountancy (STAN), Indra is a Certified Tax Consultant and a licensed attorney, authorized to practice in both Civil and Tax Courts.

Muhammad 'Abdur Rozaq

Rozaq stands out as a valued and distinguished partner at IDSP, having secured his position through demonstrated expertise and a history of notable accomplishments. His academic journey at the prestigious University of Indonesia, played a pivotal role in shaping his professional mindset and honing his skills.

Though he achieved a cum laude distinction, Rozaq committed to ongoing professional excellence. With licenses as a tax professional (Ikatan Konsultan Pajak Indonesia member) and a tax lawyer (Tax Court licensed), Rozaq skillfully navigates transfer pricing complexities in tax audits, objections, appeals, and judicial reviews. He has a track record of successfully negotiating advance pricing agreements (APAs) with tax authorities.

Senior Associates

Cornelia Flavi Anasari

Cornelia Flavi Anasari is a Tax and Legal Consultant, holding degrees from Universitas Brawijaya and Universitas Kristen Maranatha. She is a member of the Indonesian Tax Consultants Association (IKPI) and a licensed tax lawyer authorized to practice before the Tax Court, and also holds a Certified Mining Legal Consultant (CMLC) license as a member of PERKHAPPI.

Her practice focuses on Tax Law, Tax Compliance, SP2DK handling, Tax Audits, Tax Objections, Tax Appeals, and Tax Litigation, with a strong track record in managing complex disputes, including the successful negotiation of Bilateral Advance Pricing Agreements (BAPA) with tax authorities.

Nadia Saleh

Nadia Saleh is a tax and accounting professional with an academic background from the University of Indonesia (UI) and ABFI Perbanas. She is a member of the Indonesian Tax Consultants Association (IKPI) and a licensed tax lawyer authorized to practice before the Tax Court.

Her practice focuses on International Tax and Transfer Pricing, with extensive experience in handling tax audits, objections, appeals, and judicial reviews. Drawing on her combined expertise in taxation, accounting, and finance, Nadia delivers comprehensive, risk-focused solutions for clients across various industries.

Diana Putri Agustin

Diana Putri Agustin is a tax professional with an academic background from the University of Indonesia. She is a member of the Indonesian Tax Consultants Association (IKPI) and a licensed lawyer authorized to practice before the Tax Court, with a strong foundation in domestic and international tax matters.

Her practice focuses on tax litigation, tax research, and tax planning, with experience in Transfer Pricing, including BAPA and MAP, as well as indirect tax compliance (Income Tax and VAT) in Indonesia, Malaysia, and Singapore, delivering practical and risk-focused tax solutions across industries.

Thessalonica E. Eka Puteri

Thessalonica Emmanuela Eka Puteri is a tax professional with a strong academic background, having graduated from Universitas Brawijaya. She began her career as a tax consultant and has since developed extensive experience in handling a wide range of corporate tax matters in Indonesia.

Her experience includes SP2DK handling, tax audits, objections, appeals, judicial reviews, as well as international tax matters such as the Mutual Agreement Procedure (MAP) and Advance Pricing Agreements (APA). This experience underpins her commitment to professionalism and service quality, enabling her to deliver compliant, practical, and client-focused tax solutions.