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Full Court of the Federal Court of Australia · [2026] FCAFC 37

Mastercard v ACCC privilege appeal

A Full Federal Court decision about implied waiver of legal professional privilege in ACCC competition proceedings.

Full Court of the Federal Court of Australia30 Mar 2026

Plain-English explainers, not legal advice. Check the linked official source before you rely on a specific section, and get advice for your situation.

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Quick read

  • Privilege can be lost by the way a business runs its defence.
  • A Full Federal Court decision about implied waiver of legal professional privilege in ACCC competition proceedings.

Use this to check

  • Privilege waiver can happen through litigation conduct, not just by quoting legal advice.
  • Evidence about purpose, intention or belief can make related privileged material vulnerable.
  • Affidavits can create waiver risk before they are read at trial.

Decision snapshot

  1. 1

    What happened

    • The ACCC brought civil penalty proceedings alleging Mastercard entities contravened competition law in connection with commercial transactions.
    • Before an eight-week trial, Mastercard served affidavits addressing whether it held anti-competitive purposes when devising and implementing the transactions.
    • The primary judge ordered Mastercard to produce categories of documents it claimed were confidential and legally privileged.
    • Mastercard appealed.
  2. 2

    What the court had to decide

    • The Full Court considered whether implied waiver of legal professional privilege was limited to express or implied assertions about confidential communications, whether Mastercard's affidavit evidence opened its purpose to scrutiny, and whether filing or serving affidavits could support waiver before trial.
  3. 3

    What the court decided

    • The Full Court dismissed Mastercard's appeal and ordered Mastercard to pay the ACCC's costs.
    • It accepted that the primary judge correctly found implied waiver arising from Mastercard's affidavit evidence opening the relevant purpose subject matter to scrutiny.

Practical impact

Practical read

  • Privilege can be lost by the way a business runs its defence.
  • If affidavits or evidence put decision-makers' purposes into issue, the business may open privileged legal advice and internal communications to scrutiny even if it never quotes that advice.

Useful next steps

  • Privilege waiver can happen through litigation conduct, not just by quoting legal advice.
  • Evidence about purpose, intention or belief can make related privileged material vulnerable.
  • Affidavits can create waiver risk before they are read at trial.
  • Regulatory litigation needs privilege review before evidence is served, not after.
  • Run a privilege review before serving affidavits, witness statements or board evidence.

Practical read

This is a litigation-control case with a very practical business lesson. Mastercard did not simply lose privilege because it talked to lawyers. The issue was that its evidence put the company's commercial purpose and state of mind into the contest. Once that topic was opened, the Court accepted that fairness could require production of privileged communications connected with that same subject matter.

The Full Court dismissed the appeal. It held that implied waiver is not limited to cases where a party directly states the content of privileged advice. Conduct can be inconsistent with maintaining privilege if the party advances a case that makes the privileged material part of the fairness of the dispute.

For businesses dealing with regulators, this matters early. Before serving affidavits, witness statements or board evidence, the legal team should review whether the evidence relies on purpose, intention, advice, belief or state of mind. Once that evidence is served, privilege risk may already have shifted. It is much harder to tidy this up after the trial strategy has been committed.

Checks to run

Key points

  • Run a privilege review before serving affidavits, witness statements or board evidence.
  • Identify any evidence that says why the business acted, what it believed or what purpose it held.
  • Keep legal advice, commercial strategy and witness preparation channels clearly separated.
  • Do not assume privilege is safe just because the advice itself is not quoted.
  • Use one controlled litigation communication channel for regulator proceedings.

Key takeaways

  • Privilege waiver can happen through litigation conduct, not just by quoting legal advice.
  • Evidence about purpose, intention or belief can make related privileged material vulnerable.
  • Affidavits can create waiver risk before they are read at trial.
  • Regulatory litigation needs privilege review before evidence is served, not after.

Related topics

Consumer Law & TradingContracts & Commercial

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