Two prominent Western Australian property entrepreneurs have initiated legal proceedings in the WA Supreme Court against their long-time accounting firm, HLB Mann Judd, alleging widespread professional negligence in the management of their family trusts and taxation affairs.

The claims have been brought separately by Dale Alcock and Garry Brown-Neaves, former co-founders of the ABN Group, one of Australia’s largest residential building companies, which they split following a buyout in 2016.

The writs, filed on 26 June, span decades of alleged misconduct, with Alcock’s documents claiming systemic failures in accounting and tax advice from 1990 through to 2026.

The plaintiffs allege that the firm provided incorrect guidance regarding tax liabilities, including family trust distribution tax and franking deficit tax obligations, and in some instances allegedly misled them into believing such liabilities did not apply.

They further claim the services failed to meet statutory guarantees, lacked due care and skill, and were not fit for purpose, resulting in significant financial harm.A 2025 audit by the Deputy Commissioner of Taxation reportedly alerted Alcock to concerns that triggered the legal action.

Both Alcock and Brown-Neaves are seeking compensation for tax penalties, interest charges, and legal costs incurred as a result of the alleged mismanagement.

Brown-Neaves has also filed multiple writs relating to accounting services provided between 1999 and 2017, claiming substantial liabilities arising from invalid trust elections and associated penalties.He also alleges personal exposure to tax debts due to his role as a director of a corporate trustee.HLB Mann Judd has declined to comment on the allegations.The exact financial value of the claims has not been disclosed, but both parties argue they have suffered extensive and ongoing losses.