The move follows reviews which found a need for a material uplift associated with issues like compliance and anti-money laundering and counter-terrorism financing.
The company said the bulk of the writedown was associated with the acquisition of the Home Building Society in 2007.
It said that as of the end of February, BOQ considered that the share price and resulting market capitalisation did not accurately reflect the value of the company’s assets and liabilities.
“Accordingly, BOQ has increased the discount rate used to determine the value in use,” it said.
“This reduces the gap between BOQ’s market capitalisation and the value in use of the cash-generating units in which goodwill is associated.”
Managing director Patrick Allaway said the bank was in a strong financial position and was supported by increased capital and liquidity buffers as well as cash earnings and sound asset quality.
“The investment in our integrated risk program will further strengthen our operational resilience,” he said.
“Our shifted focus on strength and simplification while digitising BOQ is designed to deliver a low-cost bank with strong foundations.”
The company said the risk management work was well underway and followed a review which found a “material uplift is required in respect of BOQ’s operational resilience, risk culture and anti-money laundering and counter terrorism program and compliance”.
“BOQ is engaging proactively with regulators in relation to the scope and governance of the integrated risk program with external subject matter experts engaged to assist.”
It said it had also started work to simplify its operating model through the reduction of duplication and delivering operational efficiencies.
The company said banking regulator APRA had also approved the redemption of $200 million in floating rate subordinated notes.