UBS, the biggest European casualty of the US subprime crisis, surprised investors on Thursday by announcing that it would raise slightly more than expected through the deeply discounted rights issue approved by shareholders last month to boost capital ratios.

The move came as Marcel Rohner, chief executive, said in a Swiss media interview to be published on Friday that UBS did not foresee more massive writedowns in its troubled US credits on the scale of the $19bn hit announced last month.