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.

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.

Senior Associates

Nur Hayati Fajriah

Nur Hayati Fajriah is a tax and accounting professional with experience in accounting services, taxation, and financial consulting. She is a licensed Tax Court Attorney and holds Brevet A and B certifications, with a strong background in supporting corporate and individual taxpayers.

Her experience includes managing end-to-end accounting processes and financial statement preparation for multinational companies, handling comprehensive corporate tax obligations, and assisting with tax administrative matters such as NPWP registration and VAT confirmation. She has also been involved in resolving tax disputes, including SP2DK processes and tax audits, while ensuring compliance with applicable regulations across various industries.

Syamsu Erwin Darmawan

Syamsu Erwin Darmawan is a tax professional specializing in tax dispute and compliance, with extensive experience supporting and executing cases ranging from SP2DK processes to judicial reviews, as well as handling transfer pricing and tax audits. He is Brevet A&B certified and a licensed Tax Court Attorney authorized to represent taxpayers before the Tax Court, with a strong track record in managing objections, appeals, and restitution processes for VAT and Corporate Income Tax.

Throughout his career, he has represented notable multinational and national companies across various industries, including successfully overturning objection results in tax appeal processes and preparing comprehensive transfer pricing documentation. He has also led tax audit processes through to the appeal stage, consistently delivering positive outcomes for clients.

Naomi Dova Nathalia Sitanggang

Naomi Dova Nathalia Sitanggang is a tax professional specializing in tax dispute and compliance, with experience handling SP2DK processes through to judicial review, as well as transfer pricing and tax audits. She is Brevet A&B certified and has been involved in managing objections, appeals, and tax restitution for VAT and Corporate Income Tax.

Her experience includes preparing transfer pricing documentation for clients in trading and manufacturing industries, supporting tax audits up to the judicial review stage, assisting in VAT refund processes, and ensuring accurate and timely tax reporting through systems such as Coretax.

Dyanes Sarai Putri Rezeki

Dyanes Sarai Putri Rezeki is a tax professional specializing in transfer pricing, tax dispute resolution, and compliance, with experience handling cases from tax audits through to judicial review. She has been involved in SP2DK processes, objections, appeals, and VAT and Corporate Income Tax restitution, as well as managing transfer pricing engagements and tax compliance matters.

Her experience includes supporting tax appeal cases, preparing transfer pricing documentation across various industries, and handling end-to-end tax compliance processes, including financial statement reconciliation and tax return preparation, with a strong focus on accuracy and regulatory compliance.