Australia's people have been given unprecedented access into the tax affairs of the nation's largest private companies and the information raises more questions than it answers.

But one thing it is sure to do is to increase suspicions that corporate Australia is not paying its fair share of tax.

The data revealed that about 30 per cent of private companies with incomes of A$200 million ($224.5 million) or more pay no tax at all. It contains the names of many prominent Rich List families.

This does not mean companies on the list are doing anything illegal. As Tax Commissioner Chris Jordan pointed out when he released the information, there are legitimate reasons why a company might pay no tax despite having a large income. It might have carried forward losses from another year, or not have made any profit on its income, or have sunk a lot of money into an investment that year.


In fact, the list does reveal that some companies are paying a big whack of tax. Iron ore billionaire Gina Rinehart's Hancock Prospecting, for instance, paid A$466 million in company tax on A$2.85 billion in revenue.

But the data also revealed that between them the 321 companies on the list have more than 11,000 associated entities, such as other companies, superannuation funds, family trusts, joint ventures and partnerships.

The tax and business affairs of the wealthy are undeniably complicated, but that is a huge number of associated entities by any measure, and a lot of nooks and crannies through which to funnel income to lower tax jurisdictions.

Without a doubt some companies will use complex legal structures and overseas-based entities to reduce their taxable income as much as possible.

The revelations come as the Turnbull Government is considering a cut to the corporate tax rate after a concerted push by the business lobby. Although can anyone remember a time when the business lobby hasn't been pushing for lower taxes?

The news will only serve to strengthen the perception that corporate Australia is not paying its fair share of tax and make any corporate tax cut much harder to sell to the general public.

And any tax cut will have to be passed by the Senate, where the Greens are likely to hold the balance of power after this year's election. Already the Greens have said they will block any company tax cut after these revelations.

The revelations are part of the Government's fight on corporate tax avoidance, particularly by multinationals who can use their global structures to shift income to lower-tax or no-tax jurisdictions.

When the private company disclosure law was first introduced by the then Labor Government it would have captured any private company with an income of A$100 million or more. But this was bumped up to A$200 million by the present Government following the nonsensical argument by the business lobby that revealing the affairs of rich families would have made them takeover targets.

This appears to have given some large private companies the opportunity to restructure, such as splitting into two or more parts, to bring their taxable income below A$200 million and so avoid having to report.

The law follows other similar laws which also force large public companies to disclose more of their tax affairs.

None of the data actually tells us much. It's really all headline figures - income and tax paid.

But at least it raises questions and will force companies to better explain themselves if their headline numbers raise questions.

Many companies are signing up to the voluntary tax disclosure code, which is expected to come into effect in the next year or two. This will allow those companies which are paying their fair share to explain their tax strategies and any anomalies to the public. Those which choose not to participate will inevitably face questions about why not, with the obvious implication that they have something to hide.

Tax avoidance thrives in an atmosphere of secrecy. The more information we can get the less these companies will be able to hide behind secretive structures and avoid their obligations.

The data we received a few days ago is a start but more needs to be done.