Funds need to be held in a “financial institution” in the name of the Owners Corporation, however where the Plan is managed by a Strata Manager those funds must be held in trust with one of the institutions approved from time-to-time by the Office of Fair Trading (in NSW).
Most Strata Managers seem have those trust accounts with Macquarie; never understood why given the extent of the approved institutions available (?).
Interest is taxable, and is credited separately to the Administrative and Sinking Funds in accordance with the balance of funds held in each.
The NSW Strata Schemes Management Act (1996) requires that all financial records / statements must be tabled at each AGM, and at other times the Executive Committee can require the Strata Manager to make those records available to it with seven (7) days written notice. Depending upon the detail of the Agency Agreement that your Plan has with its Strata Manager, they may be able to charge the O/C for making those records available.