The price we would pay for keeping the farm

The Greens' claims have not gone unchallenged. According to the Minerals Council, official figures show mining is actually 71 per cent foreign-owned. The Greens say BHP Billiton is 76 per cent foreign-owned, but the correct figure seems to be 60 per cent.

No one's disputing, however, that Rio Tinto is 83 per cent foreign-owned and Xstrata is totally foreign-owned. And even if the mining industry overall is "only" 71 per cent foreign-owned, that's still a remarkably high proportion.

What's more, the funding for the present huge expansion in the mining sector, which is likely to continue for quite a few years, is safe to come mainly from foreigner investors. If so, their share of the ownership of our mining companies is bound to go higher.

So why don't we just pass a law prohibiting foreigners from buying Australian mines and farms - or at least limiting foreign purchases in some way?

Sorry, it ain't that simple. Before we did that, we'd need to be sure we were prepared to pay the price of keeping what's left of Australia in Australian hands.

All spending on new physical investment - whether on homes, business equipment, mines and other structures, or public infrastructure - has to be financed by saving. For every $1 billion we invest this year, the money has to come from somewhere and, in fact, it has to come from us saving $1 billion this year.

The saving can be done by households, by companies retaining some of their after-tax profits, or by governments raising more in revenue than they spend on recurrent purposes. There's just one escape clause: we can also finance our investment spending by using the savings of foreigners.

We can either borrow from them - thereby adding to Australia's foreign debt - or we can sell them some Australian asset: real estate, an existing business, shares bought on the stock exchange or the right to set up a new business with their own money.

If we borrow their savings, the money will have to be repaid in due course, and we'll have to pay interest to them. If, instead, we sell off part of the farm, the after-tax profits the foreigners make from their share of the business will belong to them. They can either reinvest those profits in the business (which will increase the amount of the farm they own) or take them out of the country.

The Greens estimated that, over the next five years, the foreign owners of our mining companies will be entitled to after-tax profits of $265 billion, but will reinvest four dollars in every five, taking home only about $50 billion.

I'm not sure how accurate those figures are, but they do illustrate a point about which everyone agrees: a very high proportion of the big profits foreigners are making from our mining sector is being ploughed back into expanding the sector.

Does all this shock you? It's been going on, year after year, pretty much since white settlement. Because this is a big country packed with natural wealth, but with a relatively small population, Australians have never saved enough to finance all the abundant opportunities for economic development and enrichment.

So we've always invited foreigners - first the British, then the Americans, then the Japanese and now, to some extent, the Chinese - to bring their capital to Australia and join us in fully exploiting our nation's potential.

In other words, we've always been a "capital-importing" country. We've almost always run a surplus on the capital account of our balance of (international) payments, with more foreign capital funds flowing in than Australian capital funds flowing out. These funds include borrowed money and money for the purchase of physical assets and businesses ("equity" capital).

(It's worth remembering, though, that in recent decades we have had a lot of Australian money flowing out as our superannuation funds have invested in foreign shares and bonds, and Australian transnational corporations have expanded abroad. So while the rest of the world has been acquiring more of Australia, we've be acquiring more of the rest of the world.)

If we almost always run a surplus on the capital account of the balance of payments, it follows as a matter of arithmetic that we run an exactly offsetting deficit on the current account of the balance of payments. Thus the capital account surplus allows our exports to exceed our imports and covers the cost of our net payments of interest and dividends to the foreign suppliers of capital.

But why have we always invited foreigners to bring their savings to Australia and participate in the economic development of our nation? Because of our impatience to be richer, our desire to raise our material standard of living.

And because, as part of that, we've always been confident we were getting our fair share of the benefits. Any profits the foreigners make, we tax. Any minerals they extract from our land, we charge them royalties (though, with world commodities prices so high at present, probably not enough, which is what the new mining tax is about). But the benefits of economic activity exceed the profits made. It also generates a lot of jobs, directly and indirectly. Those jobs go mainly to Australians and help feed their families.

We could perhaps borrow more from foreigners so as to reduce their ownership of our real estate and businesses, but there are limits to how far debt can substitute for equity and limits to how much debt the nation should take on.

So if we want to impose new restrictions on how much foreigners own, it's pretty safe to involve less economic development, slower economic growth than we were expecting and a more slowly rising standard of living.

That wouldn't worry me much, but many people would see it differently. Point is: don't imagine restricting foreign ownership would come without a price to be paid.