The head of BHP Billiton gets paid about 200 times as much as the average Australian. Back at the start of the 1980s it was six or seven times as much.
The stark finding is in research that uses BHP records dating to 1887 to plug gaps in what is known about long-run trends in Australian executive remuneration.
"What we see is a relatively high ratio of BHP chief executive salary to Australian earnings at the turn of the 20th century, around 50 times average earnings, slowly dropping throughout the century, save for a spike in the Second World War," said Melbourne University economist Mike Pottenger. "Then with the arrival of Paul Anderson as chief executive in 1998 there's a vertical jump. He was paid more than 200 times average earnings.
"Anderson was the first internationally sourced chief executive since the very first, William Patton, who was hired for £4000 in 1887.
"Anderson's successors, Brian Gilbertson, Chip Goodyear, Marius Kloppers and Andrew Mackenzie, have all earned around 200 times the average - it has become the new normal."
Mr Mackenzie, who took charge of BHP last month, is expected to earn about 25 per cent less than his predecessor, Mr Kloppers, in a reflection of the tougher times being felt across the industry.
Even so, he can still earn a maximum of $US12.58 million a year if BHP performs exceptionally well.
Working with BHP historian Geoffrey Blainey and inequality researcher Andrew Leigh, who is now a Labor member of Federal Parliament, Dr Pottenger constructed a range of likely salaries for the years 1887 to 1984 using the few internal memos that mentioned salaries and the known relationship between the chief executive's salary and BHP director fees.
From 1987 he used the executive remuneration reported in BHP annual reports and later the total remuneration including stock options and incentives.
"At all times our estimates have been conservative," Dr Pottenger said.
"If critics want us to exclude the incentives and options, we are happy to point out that without them the CEO's salary is still 100 times the average - roughly double its previous peak and far higher than anything thought possible during the 1970s and 1980s."
Data provided by Egan Associates on the average CEO remuneration at Australia's top 100 companies for the past few decades suggests BHP's experience has been typical.
"In BHP's case, the merger with Billiton near the turn of this century made it a truly global company," Dr Pottenger said.
"Also just before the merger there was an air of desperation in the company. Its 1999 annual report was titled 'Under Pressure', the 2000 report was titled 'Coming out of a tight corner'."
He said BHP and other newly globalised companies "all want to hire a chief executive who is better than the global median".
"The only way to do that is to bid up salaries," Dr Pottenger said.