Alarm bells were ringing at the Australian Tax Office in 2008 as auditors confronted a wave of aggressive tax strategies that grew out of the mining boom – and one of the key suspects was the rise of marketing hubs.

While BHP Billiton and Rio Tinto are Australia's biggest taxpayers – last year they paid $US7.2 billion (about $9.4 billion) and $US6.2 billion (about $8.1 billion) in Australian taxes and royalties – they also run the biggest marketing operations in Singapore. They were logical early targets for tax audits.