NO DIM SUMS

Boasting about size may be poor form and the sign of an arriviste. Yet perhaps China can be forgiven any lapse of decorum. The country now boasts three of the world's top 10 companies by market capitalisation. It has the world's biggest bank, Industrial and Commercial Bank of China, and the world's largest telecoms operator, China Mobile. PetroChina is second only to Exxon, while life assurer China Life is second to none.

Some of this is down to recent market movements. After racking up a terrible performance in 2008, the Shanghai Composite index is up by 17 per cent this year. Thus dual-listed ICBC, worth $180bn based on its Shanghai price (over 70 per cent of the bank is held by the Chinese government), can now buy HSBC twice over and still have enough change for several of the biggest American banks.

Chinese and US banks have switched places in other ways. Remarkably, the US has a bigger proportion of banking assets in state hands and also more red ink. ICBC, by contrast, made more net profits than any other bank in 2007, and earned nearly $14bn in the first nine months of 2008.

Indeed, three of the 20 in 2007 biggest earnings hauls came from Chinese companies. The net profits that China Mobile made then, its latest full year, would buy British Telecom outright, throwing in Telecom Egypt for good measure. Six years ago, the country did not get a look in.

Size, however, can generate its own momentum. Fund managers move in packs, while index trackers have no option but to load up on the likes of ICBC and PetroChina. But size, like sentiment, can turn on a sixpence.

No country knows this better than Japan, home to eight of the 10 biggest companies by market capitalisation in 1989. After all, 20 years ago, the eight were worth $550bn – more than the value of Japan's entire banking and communications sectors today.