A boom-time private equity deal structured by Macquarie Group has gone bad, triggering $630 million in losses including $240 million in write-offs by three big Australian industry super funds and a hybrid debt fund managed by AMP Capital Investors.

The collapse of the East London Bus Group Ltd and its sale back to the original vendors for a fifth of the purchase price provides a rare opportunity to look at the inner workings of a contemporary private equity trans­action and the high risks taken by ­investors.