Agricultural Bank of China was always going to be the last of China's big state-controlled banks to sell shares in an initial public offering but nobody thought it would take this long. The bank's IPO has been delayed repeatedly since 2006, when Industrial and Commercial Bank of China, the last of its big peers, raised $22bn in a simultaneous Hong Kong and Shanghai listing.

The delays were caused, among other things, by the fact nobody knew how many bad loans Agricultural Bank had on its books. There was also debate over whether it should remain a lender that carried out Beijing's agricultural policies instead of focusing purely on profit.

Those issues appear to have largely been resolved, but now the problem is that all its large competitors are also rushing to raise money and stock markets in Hong Kong and Shanghai have fallen.