The Australian Retirement Trust has downgraded some of its office towers by as much as 15 per cent as the sector faces a reckoning and industry super funds turn to equities to cushion poor real estate performance.

This far outstrips Dexus’ 6 per cent write-down of its diversified portfolio last month and Charter Hall’s 2.8 per cent downgrade to its managed property portfolio, as regulators warn of over-inflated valuations.