The corporate regulator has issued a scathing report card on the way the $4.3 trillion super industry and the country’s major auditing firms value unlisted assets, after it emerged that the nation’s second-largest super fund had written down a US investment worth almost half a billion dollars.

The Australian Securities and Investments Commission’s first review of the sector’s financial reports and audits found super funds’ disclosure about non-listed assets was often inconsistent and unreliable, making it difficult for members to be confident about the value of their holdings.