Commercial Bank of Australia Ltd v Amadio
High Court of Australia · 1983
Commercial Bank of Australia Ltd v Amadio (1983) 151 CLR 447
Their son's business was failing. The bank had the guarantee signed. When does the law step in and undo a bargain nobody forced anyone to sign?
"Ought to know" is not constructive notice. The appellant submitted that Amadio imported the principles of constructive notice ([150]); a unanimous Court held that Mason J "cannot be taken to have supported the importation of the concept of constructive notice into the operation of the principle he enunciated in Amadio" ([155]). What Mason J was describing was "wilful ignorance, which, for the purposes of relieving against equitable fraud, is not different from actual knowledge" ([156]) -- the same reading Deane J had given the bank's conduct in Amadio itself, where its officer "simply closed his eyes to the vulnerability" of the guarantors (151 CLR 447 at 478-479).
The language survives, and it does not require an express finding of actual knowledge. The primary judge had found only that the lender's solicitor "should have known" the borrower was bound to lose his equity; Kiefel CJ, Keane and Gleeson JJ accepted that this "did not rise to an unequivocal finding of actual knowledge" but held "a finding in such terms was not essential", because "the question is whether Mr Jeruzalski's appreciation of the appellant's special disadvantage was such as to amount to an exploitation of that disadvantage" ([44]). Their Honours approved Kakavas's endorsement of Mason J's formulation at 462 ([45]) and found relief established because the lender's agent "had sufficient appreciation of the appellant's vulnerability, and the disaster awaiting him" ([46]). The inquiry is into what the stronger party appreciated, not into what a diligent enquirer would have discovered.
How far Kakavas reaches is unsettled, and the distinction to hold onto is between notice and knowledge. Bell CJ takes constructive knowledge to mean "knowledge of facts from which a person ought to have known that another person was suffering under the relevant special disadvantage", and constructive notice to mean "being on notice of facts that might lead on inquiry to discovery of the existence of a special disadvantage" ([6], [10]). Only the second is clearly insufficient. In his Honour's view "the only way to reconcile Kakavas and Thorne ... is that Kakavas must be understood as standing as authority only for the negative proposition that constructive notice is insufficient", which would put the contrary line of Western Australian Court of Appeal decisions in error ([9]) -- though he expressly declines to reach a concluded view ([11]). His Honour also reads Thorne at [38] and Stubbings at [44] as demonstrating "a retreat from Kakavas' apparent insistence on a requirement of actual knowledge or wilful ignorance". So do not teach or argue the wilful-ignorance reading as settled.
What happened?
An elderly couple guaranteed their son's building company and mortgaged their property to secure it. They had limited English and little business experience, and their son had told them the guarantee would be for about $50,000 and would run about six months. It was unlimited in both. When Mr Amadio remarked on signing that the mortgage was "only for six months", the bank's officer "was then at pains to point out that there was no such limitation of time" — and the primary judge still found that when they signed they believed their liability limited both in amount and in time, a belief induced by what their son had told them (151 CLR 447 at 454). The bank knew the company could not pay its debts as they fell due; the parents did not, and they were relying on the son, whom the bank's officer described as "the dominant member of the family" (at 477).
What did the Court decide?
The guarantee and mortgage were set aside. The Amadios "lacked assistance and advice where assistance and advice were plainly necessary if there were to be any reasonable degree of equality between themselves and the bank" (per Deane J at 477). Mason J put the principle in the form now usually quoted: the disabling condition must be "one which seriously affects the ability of the innocent party to make a judgment as to his own best interests, when the other party knows or ought to know of the existence of that condition or circumstance and of its effect on the innocent party" (at 462).
Deane J added the step that decides most problems. Where the weaker party was under a special disability and "that disability was sufficiently evident to the stronger party to make it prima facie unfair or 'unconscientious' that he procure, or accept, the weaker party's assent", then "an onus is cast upon the stronger party to show that the transaction was fair, just and reasonable" (at 474). The bank could not discharge it.
Proposition
What is the principle?
A transaction may be set aside for unconscionable dealing where one party suffers from a special disadvantage that seriously affects their ability to judge their own best interests, the other party knows or ought to know of it, and that other party unconscientiously takes the benefit of the transaction. Where the disability is sufficiently evident to make acceptance prima facie unconscientious, the onus shifts to the stronger party to show the transaction was fair, just and reasonable.
Why does this case matter?
Notice what the doctrine does not reach. It is not a remedy for a harsh bargain, and it is not a remedy for inequality of bargaining power: Mason J chose the word "special" precisely "to disavow any suggestion that the principle applies whenever there is some difference in the bargaining power of the parties" (at 462). A candidate who reasons from "the bank was much stronger than these elderly parents" to a conclusion has reproduced the argument the qualifier was written to exclude.
The other thing to carry away is that Amadio is cited far more often than it is won, and that its most quotable phrase has been fought over ever since. Kakavas held in 2013 that it does not import constructive notice; Thorne in 2017 and Stubbings in 2022 quoted Mason J's "knows or ought to know" without that gloss; and intermediate appellate courts have since remarked on the difficulty of reconciling the two lines. The formulation you copy out of 1983 is not one you can quote into 2026 unqualified — check what the court you are in has said about it.
Exam and application relevance
The element candidates skip is knowledge, and it is also the one they most often get wrong. A problem describing a plainly disadvantaged party is half an answer; the marks are in what the stronger party appreciated. Do not argue it as a duty to enquire: being on notice of facts that might, on inquiry, have turned up a special disadvantage is not enough. The strongest version of the argument is that the transaction was so obviously improvident, or the vulnerability so plain, that the stronger party cannot be heard to say the possibility never occurred to it. Whether anything short of that will do — knowledge of facts from which the disadvantage ought to have been recognised, without shutting one's eyes to it — is genuinely unsettled after Kakavas, Thorne and Stubbings, and an answer that says so is stronger than one that picks a side. Point to what was in front of the defendant and say why it could not have been missed.
Amadio itself shows what carries that argument, and it is a list of ordinary facts rather than a characterisation. Mr Virgo knew the Amadios were elderly, Italian and without a good command of English; that their son had procured their agreement and was their only adviser; and that, given the company's finances, it was "vital to Vincenzo to secure his parents' signature" if it were to keep trading. Mason J's conclusion follows from the list: "[i]t must have been obvious to Mr. Virgo, as to anyone else having knowledge of the facts, that the transaction was improvident from the viewpoint of the respondents", so "it is inconceivable that the possibility did not occur" to him (at 467). Build the answer the same way.
Check your understanding
A lender takes a guarantee from a borrower's elderly parent who speaks fluent English, has run a business for thirty years, and simply misjudges the risk. Which element fails?