MacDonald v MacDonald: No Double Costs Without Full Disclosure

In MacDonald v MacDonald, 2025 ABKB 502, Justice Lema refused a Rule 9.12 application that sought to correct an alleged oversight or omission in a costs order by awarding double costs to the father, who had previously made a settlement offer. The father argued that the costs decision should have applied the double-costs provision because his offer was neither beaten nor matched in the final outcome.

Justice Lema concluded that there was no drafting error or omission. On the merits, the father did not demonstrably exceed the terms of his own offer nor achieve a clearly superior outcome at trial. Even if he had, his failure to disclose certain income details and his omission of at least one year’s tax return constituted “special circumstances” under Rule 4.29(4)(e). Those circumstances justified the court’s discretion to refuse to apply the double-costs rule.

Lema J underscored that, in family law, settlement offers must be assessed on a holistic basis—examining the overall result rather than isolating individual components—and not by “picking apart nuances” of the offer. To “better” an offer, a party must secure a net advantage when comparing the cumulative outcome to the terms of the offer. Moreover, Rule 4.29(4)(e) explicitly permits a court to withhold double costs where misconduct—such as withholding disclosure—occurs. Here, the father’s unexplained deposits and failure to file his 2023 tax return amounted to such misconduct, precluding any entitlement to double costs. Accordingly, the original order that each party bear its own costs was upheld.