All change at the top of the US Treasury, with Larry Summers taking over from Robert Rubin. Rubin has presided over a period of extraordinary bounty for the US economy, with strong economic growth and moderate inflation. Mr Summers will hope that he will be equally lucky as the general overseeing the US economy as has been Mr Rubin, who has surely chosen a good moment to quit.

There are no obvious policy differences between the two men. Summers has been effectively one of the senior figures in the treasury over the past couple of years, overseeing international relations in particular and playing a leading role in US policy towards the international financial trouble spots. He is thus vastly experienced and, as a highly regarded economist before joining the treasury, should have the necessary credentials to impress the markets.

The most obvious difference between Summers and his predecessor is that the new man would be seen as a far more outspoken figure. He will have to guard his words even more carefully now, with market analysts likely to hang on his every utterance. This could become a real test if trouble hits the US economy or the markets.