Wild swings in earnings reported by developers recently have been exaggerated by accounting standards that require firms to mark investment properties to their market value every six months and book changes in the profit and loss accounts rather than on balance sheets.

But savvy investors in property companies have understood that big write-downs taken today could turn into write-backs once the economic situation changes. And so they look instead to core operating earnings for guidance, rather than the bottom line, analysts say.

'There is no doubt that the accounting rule has injected huge volatility into property companies' profitability,' said Raphael Ding, a partner at accountancy firm Grant Thornton.

South China Morning Post