Illustration: Jim Pavlidis Cue generalised outrage. But, I was asked repeatedly, and in somewhat pleading tones, would not the media – and the Australian public more generally – appreciate that many Australian firms pay much less than the 30 per cent statutory rate each year, and that they do so for a range of legal reasons? Sure, I replied. There are any number of reasons why Australian companies may be entitled to pay less than the statutory rate, including claiming previous years' losses, depreciation, dividend imputation, various tax offsets or money spent on research and development.

There are many reasons why companies might legitimately pay no tax. But that's no reason why Australians shouldn't get to see who is paying what. And given the intense debate swirling about whether the company tax rate should be reduced from 30 per cent to 25 per cent, it would be interesting to know exactly how much they are paying. Qantas has returned to profitability, but only after several years of substantial losses. Credit:Glenn Hunt Hint: it's much less than 30 per cent.

Legislation was eventually passed to increase corporate tax transparency, and we now have access to three years of data on individual company tax paid. Australia's four big banks are our largest corporate taxpayers. Credit:Brendon Thorne This year's spreadsheet was released, somewhat suspiciously, last week on the same historic day that same-sex marriage passed Parliament. Perhaps you missed it? No matter, I can get you up to speed. The 2015-16 tax year was a particularly tough one for energy and resource companies. Credit:Bloomberg

This year's spreadsheet details the taxes paid in 2015-16 by 2043 of Australia's biggest companies, comprising 1693 Australian public and foreign-owned companies that generated an income of $100 million or more, plus another 350 Australian-owned and resident private companies with an income of $200 million or more. Together, these companies chipped in $38.2 billion to government coffers through company income tax – about 60 per cent of the $62.9 billion of total company income tax paid that year. They did so off the back of $172 billion in taxable income, giving an average corporate income tax rate of 17 per cent. I warned you it was much lower than you might think. Australia's big banks emerge as our four biggest corporate taxpayers, with the Commonwealth Bank topping the list at $3.3 billion (a tax rate of 29 per cent), followed by Westpac at $3 billion (28 per cent), NAB $2.4 billion (21 per cent) and ANZ $2 billion (24 per cent).

Rounding out the top 10 corporate taxpayers' list were Telstra $1.7 billion (29 per cent), BHP Billiton $1.3 billion (25 per cent), Rio Tinto $1 billion (23 per cent), Wesfarmers $931 million (29 per cent), AMP $681 million (11 per cent) and Woolworths $497 million (27 per cent). Together these 10 companies paid more than a quarter of all company tax collected that year. And BHP chipped in another $488 million in petroleum resource rent tax. So far, so good. Turns out, a total of 762 companies – just over a third paid within 1 decimal point of the statutory rate. And this includes a number of large multinational corporations, including Aldi, Ikea, Citigroup, Audi, BMW and Volkswagen.

But a further third – 732 in total – paid absolutely no corporate income tax. Nada. Zip. Zilch. They include: Bluescope, Alcoa, CSL, Elders, Healthscope, IBM, Lendlease, Mirvac, Origin Energy, Qantas, Pratt Consolidated Holdings, Pfizer, Shell, Seven, Transurban, Energy Australia, Chevron, Exxon Mobil, Glencore, Santos, Stocklands, Sydney Airport and Toll Holdings. Now, as explained, there are many reasons why these companies might be able to legitimately pay no tax. The most simple of which – as surprising as it might seem – being that Australia's biggest companies are not beyond turning a loss.

According to a Tax Office analysis, around 20 to 30 per cent of ASX500 firms report a net loss to their shareholders in any given year. "Importantly, this shows that even extremely large companies will sometimes make a loss in a particular year." The nation's biggest airline carrier, Qantas, for example has recently returned to profitability, but only after several years of substantial losses. The 2015-16 tax year was a particularly tough one for energy and resource companies, which faced falling prices, and were the main reason for disappointing company tax collections that year. Appearing before a parliamentary inquiry into corporate tax transparency in 2015, Treasury's then head of revenue, Rob Heferen​, observed that it was a deliberate choice of governments to allow companies to reduce their tax paid through various concessions: "So an observation that a company has an effective tax rate of less than 30 per cent is merely that – an observation of fact. It gives no insight as to whether the tax paid is appropriate or not."

Ultimately, there are benefits to taxing companies at a low rate – like promoting investment and jobs creation. Loading But the downside is that revenue has to come from somewhere to pay for all the nice things society likes, like schools and hospitals. And if it doesn't come from company incomes, it must come from wages or other sources. Paying less than 30 per cent in corporate tax may be totally legal. Only the public can determine if what is presently legal also meets society's definition of what is fair.