Australian Competition and Consumer Commission v Mastercard Asia/Pacific Pte Ltd (No 3)

This Federal Court decision is an interlocutory ruling about legal professional privilege in the ACCC's broader competition case against Mastercard. It is not the final judgment on whether Mastercard breached competition law.

The Court had to decide whether Mastercard had waived privilege by filing affidavits from two senior officers and by disclosing certain legal advice. The Court held that waiver could justify production orders framed by subject matter, not only by individual document, in the circumstances of this case. But the orders were not unlimited. They were confined to specific categories involving Mr Koh and Mr Molu, and unrelated privileged content could still be redacted.

The ACCC alleges Mastercard used strategic merchant agreements, or SMAs, as part of a strategy connected to debit card routing in Australia. According to the reasons, the ACCC says Mastercard developed a "credit leverage strategy" in about 2017 to discourage merchants from routing debit card transactions through the eftpos network and away from the Mastercard network. The alleged strategy included offering merchants incentives, including lower prices for credit card acceptance services, if they routed debit card transactions through Mastercard.

The ACCC says a substantial purpose of that strategy was to harm, disrupt or adversely affect the competitive process in the market for debit card acceptance services and thereby prevent or hinder competition. Mastercard denies those allegations. The Court said the strategy and purpose behind the SMAs are perhaps the central issue in the substantive case.

But this judgment was not about whether the strategy was unlawful. It was about what Mastercard had to hand over during the case. Mastercard had discovered many documents and claimed legal professional privilege over some of them, in whole or in part. The ACCC argued that Mastercard had lost privilege over some communications because of the way it had run its case and because of some disclosures of legal advice.

The ACCC's application had two main limbs. First, it argued implied waiver. It said Mastercard filed affidavits from two senior officers, Mr Koh and Mr Molu, that made assertions about matters such as concerns, understanding, strategy and internal consultations in a way that was inconsistent with keeping related communications confidential. Secondly, it argued that by disclosing certain legal advice, Mastercard had also waived privilege over associated material.

The reasons identify Mr Koh as a senior business leader in deal management within Mastercard Singapore's finance division, with responsibilities including reviewing and approving proposed SMAs involving Australian merchants. Mr Molu was Mastercard Singapore's chief financial officer from August 2017 and was also involved in reviewing and approving SMAs. The Court records that both men were significant figures in relation to the alleged credit leverage strategy and Mastercard's negotiation and entry into SMAs.

A major practical feature of the case was the way the ACCC framed its challenge. It did not identify a neat list of individual documents and say privilege over each one had been waived. Instead, it sought orders by reference to categories of documents dealing with the same subject matter as the affidavit evidence. The Court described that as somewhat novel, though not entirely unique.

The reason for that approach was important. Mastercard's privilege descriptions in its document lists were described by the Court as very spare, scant and unhelpful. For many emails, the descriptions gave only the date, sender, recipients, copied recipients, whether privilege was claimed over the whole or part of the document, and a generic statement that the communication was a confidential lawyer-client communication for the dominant purpose of legal advice. The descriptions did not identify the general subject matter. For non-email documents, the information was said to be even more scant.

The Court accepted that these limited descriptions made it very difficult for the ACCC to identify specific documents for challenge. The Court rejected Mastercard's submission that the ACCC's waiver case necessarily failed because it was not conducted document by document. The Court said that where the alleged inconsistency arises from a party making assertions about a particular topic or subject matter while maintaining privilege over advice on that same topic, it may be appropriate to order production by reference to subject matter. The Court referred to authority supporting that approach.

The reasons also show why affidavit drafting can be dangerous. The Court summarised parts of Mr Koh's evidence about his review of a proposed SMA, his concern that the proposed arrangement could be interpreted in a particular way, his decision to raise that concern internally, his drafting of a paper to document relevant considerations and internal consensus, and his consultation with others within Mastercard Singapore before drafting that paper. The ACCC argued that this evidence contained express or implied assertions about the content of communications with other officers, including in-house counsel, concerning the strategy and purpose behind the SMAs. Similar arguments were made about Mr Molu's affidavit, which included evidence about the considerations he had regard to when reviewing SMAs and what he knew and understood about Mastercard's strategy in entering them.

The Court's discussion of principle makes clear that the issue is not whether a witness has formally quoted legal advice. The issue is whether the privilege holder's conduct is inconsistent with maintaining confidentiality. Assertions about what was understood, what concerns existed, what was discussed internally, or what consensus had been reached can create that inconsistency depending on the facts.

The Court restated the orthodox principle from Mann v Carnell. Legal professional privilege depends on confidentiality, and there will be an implied waiver where the client's conduct is inconsistent with maintaining that confidentiality. The Court emphasised that implied waiver is not driven by some free-standing fairness test, although fairness may inform the analysis where necessary. The ultimate question is inconsistency.

The Court also said there is no closed list of circumstances that amount to inconsistency. The inquiry is fact-based. While making an express or implied assertion about the contents of a privileged communication will often be enough, waiver is not limited to those exact situations. The mere relevance of privileged communications to an issue in the case is not enough. Nor does putting state of mind in issue automatically waive privilege. Something more is needed.

Applying those principles, the Court made tailored production orders. Mastercard was ordered, within 28 days, to produce unredacted copies of documents created between August 2017 and November 2020 that constituted or recorded communications to which Mr Koh was a party and which, in whole or in part, recorded or referred to the strategy or purpose of Mastercard in offering, negotiating, approving or entering SMAs. Mastercard was also ordered to produce documents in the same period constituting or recording communications to which Mr Molu was a party and which, in whole or in part, recorded or referred to the strategy or purpose of offering, negotiating, approving or entering SMAs and or the likely effect of those SMAs.

Those orders were limited in several ways. First, they were tied to communications involving Mr Koh and Mr Molu. Secondly, they were confined to specified subject matters. Thirdly, the Court expressly allowed redactions to preserve legal professional privilege over parts of documents that did not refer to or address the relevant waived subject matter. Fourthly, the orders did not require production of documents already discovered or otherwise provided in unredacted form where Mastercard had not later requested deletion.

The Court otherwise dismissed paragraphs 2 to 5 of the ACCC's further amended interlocutory application and reserved costs. The reasons also indicate that some of the ACCC's proposed categories were too broad, so the final orders were narrower than the ACCC had sought. That is an important point for businesses. A waiver finding does not necessarily mean every related document must be handed over without limit. The court will still examine scope and may preserve privilege for unrelated content through redaction.

Most businesses will never face an ACCC case of this scale, but the privilege point is highly transferable. The same issue can arise in shareholder disputes, contract cases, employment litigation, insolvency matters and regulator investigations. The danger usually appears when a business wants to explain why it acted as it did. A witness may try to present the decision as careful, reasonable and internally considered. In doing so, they may refer to concerns, consultations, internal consensus, understanding or strategic purpose. That can create an argument that related communications should be opened up.

This case also shows that discovery practice matters. If your privilege log gives only skeletal descriptions, the other side may say it cannot fairly test the claim document by document and ask the court for broader category-based relief. The Court accepted that possibility here because the descriptions were so limited. A better privilege log will not eliminate waiver risk, but it can reduce the chance that broad subject-matter orders are seen as the only workable solution.

There is also a more nuanced point. The Court did not treat waiver as all-or-nothing. The orders were confined to particular categories involving Mr Koh and Mr Molu, and unrelated privileged material could still be redacted. That means businesses should not assume that once waiver is argued, every privileged communication is lost. Scope still matters. Subject matter still matters. The identity of the relevant witness still matters.

For practical case management, evidence preparation and privilege review should be coordinated. The legal team drafting affidavits should know what documents are on the privilege list, how they are described, and whether any legal advice has already been disclosed. If a witness needs to explain commercial purpose or state of mind, the team should test whether the point can be made by reference to objective facts rather than internal communications. If not, the business should make a conscious decision about the privilege consequences before filing the evidence.

The judgment was delivered by Wigney J in the Federal Court of Australia on 29 August 2025. The hearing date recorded in the reasons was 3 July 2025. The orders required production within 28 days of the making of the order.

The reasons also note that some evidence extracts were redacted because they were subject to interim suppression orders, and merchant names were anonymised. The Court said whether final suppression orders would be made was to be determined at an interlocutory hearing in December 2025. That means some aspects of public reporting may remain constrained or may change depending on later orders.

This page should therefore be read as an explanation of the privilege ruling as published, not as a final account of every later procedural development in the broader ACCC proceeding.