From Mr William Gamble.

Sir, One reason the officials in Beijing feel that their overheated economy is reasonable is because they have few ways to deal with it. As Richard McGregor pointed out in his excellent article on reinvesting by Chinese companies ("Chinese growth at fastest pace for decade", July 19), much of the growth in China comes from companies reinvesting their profits. Unfortunately they reinvest in lines of businesses that they know nothing about, which makes the hope of further profits doubtful. Worse, their diversification increases competition and drives down margins.