CORAA

SIA 18 — Related Parties

ICAI Internal Audit Standards Board · Legacy standard, March 2013
Reviewed 1 October 2026

SIA 18 is about evidence that related-party transactions are properly captured by the entity's internal controls and are consistent with its code of conduct and with disclosure law. If that evidence is insufficient, the standard requires disclosure in the report.

This page covers SIA 18 as it stands in ICAI’s October 2022 compendium. ICAI’s February 2026 compendium, applicable from 1 April 2026, renumbers the standards, so check the current number and text in that compendium before citing it in a report.

What the internal auditor has to do

  • Obtain evidence that internal controls properly capture related-party transactions.
  • Check that those transactions are consistent with the entity's code of conduct and with disclosure law.
  • Disclose the position in the report if the evidence is insufficient.

How SIA 18 shows up in the internal audit file

  • The work done on the controls that identify and record related-party transactions.
  • The evidence obtained on consistency with the code of conduct and disclosure requirements.
  • Where evidence fell short, the disclosure made in the report.

Common mistakes in practice

  • Accepting management's list of related parties without testing the controls that are meant to capture them.
  • Saying nothing in the report when the evidence on related-party transactions was insufficient.

The file checklist and the mistakes above are practice points drawn from the requirements of the standard. They are not text from the standard.

Related standards

SIA 370 · Reporting ResultsSIA 320 · Internal Audit EvidenceSIA 120 · Internal Controls

Status and source

This standard is described here as it stands in the October 2022 compendium, which is the earlier set. ICAI's Internal Audit Standards Board lists its Compendium of Standards on Internal Audit (as on February 2026) as applicable from 1 April 2026 (source: the Board's compendium page, checked on 1 October 2026). That compendium renumbers the standards, so check the current number and text there before citing this standard in a report. ICAI's compendium page does not say whether the standards are mandatory or recommendatory, so we do not describe any standard as mandatory. In the October 2022 compendium this standard is still headed as recommendatory in the initial period and mandatory from a date to be notified by the Council of ICAI, and that date is left blank.

These pages summarise each standard as it stands in ICAI's Compendium of Standards on Internal Audit (as on 1 October 2022), working from an extract of that document. They are summaries and close paraphrases, not the text of the standards. ICAI's Internal Audit Standards Board lists its Compendium of Standards on Internal Audit (as on February 2026) as applicable from 1 April 2026 (source: the Board's compendium page, checked on 1 October 2026). For that current set we have only the titles, taken from the Board's 2025-26 annual report; its text is available from ICAI through a registration form on the compendium page and is not summarised here. ICAI's compendium page does not say whether the standards are mandatory or recommendatory, so we do not describe any standard as mandatory. Before you cite a number, a paragraph or a status in a report, check the February 2026 compendium. internalaudit.icai.org

Free working files for SIA 18

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Editable formats and tools from CORAA’s internal audit library that put SIA 18 into practice. Free to use.

Related Party Transactions Internal Audit Checklist →

SIA 18 — frequently asked

What is SIA 18?

SIA 18, Related Parties, is a Standard on Internal Audit issued by the Internal Audit Standards Board of ICAI. SIA 18 is about evidence that related-party transactions are properly captured by the entity's internal controls and are consistent with its code of conduct and with disclosure law. If that evidence is insufficient, the standard requires disclosure in the report. It was published in March 2013 and kept its original number.

Is SIA 18 mandatory?

ICAI's compendium page does not say whether the Standards on Internal Audit are mandatory or recommendatory, so we do not describe SIA 18 as mandatory. ICAI's Internal Audit Standards Board lists its Compendium of Standards on Internal Audit (as on February 2026) as applicable from 1 April 2026 (source: the Board's compendium page, checked on 1 October 2026). SIA 18 as described on this page is from the earlier October 2022 compendium. The February 2026 compendium renumbers the standards, so check the current number and text there before citing it in a report.

What should the internal audit file show for SIA 18?

The work done on the controls that identify and record related-party transactions. The evidence obtained on consistency with the code of conduct and disclosure requirements. Where evidence fell short, the disclosure made in the report.

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