The largest 500 private businesses have accounted for between 5 and 6 per cent of the nation's total reported business revenue over the past decade.

Last year was no exception, with their $248 billion in revenue coming in at 5.2 per cent of the $4.8 trillion generated by all reporting listed and private businesses. Collectively, these private companies represent a microcosm of the nation in many regards, including their mix of industries and the profitability of the best performers.