Trust amounts are taxes a business collects or withholds on the government's behalf and holds in trust for the Canada Revenue Agency — principally GST/HST collected from customers and source deductions (income tax, CPP, and EI) withheld from employees' pay. They are legally distinct from a business's own taxes, such as corporate income tax.
Because these amounts never belonged to the business, they are treated more seriously than ordinary tax debts. Unremitted trust amounts can pierce the corporate liability shield and be assessed against directors personally, and they remain collectible by the Canada Revenue Agency even while a related assessment is under objection — unlike disputed income tax, which is generally not collected during an objection.