But even these enormous sums do not buy much: railways account for 40% of the government's total transport budget but only 8% of the journeys made.

ECONOMIST: Railways

So even when the poor do spend more on food, they do not buy the stuff that is most nutritious or the best value.

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There is some currency hedging and when the shops make big advance orders for Christmas products, for example, they will buy the currency to pay for them straight away, even if they do not need to make the payment for several months.

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But whatever the chosen technology, we urgently need to do something about the problem of online identity, and not just so that we can bank safely or buy even more consumer goods.

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Unibanco and Safra would be left far behind the top two if they did not buy it, and analysts think the families that own them would probably then sell (they might do so even if they are the successful bidders).

ECONOMIST: Brazilian banks