Parkin v Boral Limited (Materiality Evidence Ruling)

Parkin v Boral Limited (Materiality Evidence Ruling) involves an objection to expert evidence on the issue of materiality in a case related to continuous disclosure obligations under the Corporations Act 2001 (Cth). The case is being heard in the Federal Court of Australia, with Justice Bromberg presiding. The primary legal issue the court needed to decide was whether the proposed expert evidence on materiality should be admitted and, if so, whether it should be excluded under s 135 of the Evidence Act 1995 (Cth) due to potential wastage of time. The court also considered the broader issue of the escalating costs of expert evidence in class actions.

In its reasoning, the court found that while materiality was an important issue in the case, the expert evidence in question was of limited utility. The court observed that materiality is generally an evaluative assessment informed by commercial common sense, rather than a matter that requires extensive expert analysis. The court noted that expert evidence on materiality often over-intellectualises a concept that is supposed to be understood by all. Despite this, the applicants had retained experts to buttress their case, leading to a reactive stance by the respondents. The court acknowledged that the bulk of the prejudice identified could be mitigated by appropriate rulings and that the issue ultimately came down to the weight to be afforded to the evidence. The court concluded that the evidence was sufficiently relevant to be placed before the court but that its weight would be addressed in final submissions. The court rejected the notion of excluding the evidence under s 135 of the Evidence Act, as the savings associated with exclusion were not sufficiently worthwhile. The court also rejected discretionary exclusion under s 192 of the Evidence Act, noting that the evidence had limited probative value and that there was unlikely to be any undue waste of time or oppression given the already voluminous material in the case. The court emphasised the recurring problem of escalating costs of expert evidence in class actions, where parties often retain experts to buttress cases that should be understood by all.

The court's final order was to stand the matter over to 10:15 am on 3 September 2025. The court stressed that it would keep an open mind and hear the materiality evidence and submissions as to its weight in the case, without rejecting or excluding the evidence. The decision highlights the court's approach to the admissibility and utility of expert evidence in cases involving materiality and the broader issue of controlling costs in class actions.