Executives at UBS AG are concerned that pending bonuses will be inadequate to retain top talent at the Swiss bank, one of the hardest hit during the financial crisis, the Wall Street Journal reported on Thursday.

The report cited a person familiar with the matter as saying there were concerns within the investment bank about defections to competing banks at a time when UBS is hiring to rebuild.

The bank sent a memo to employees this week that the announcement of 2010 bonuses would be delayed by a week to February 16, the WSJ said. It said payments have been delayed from late February to early March.

Another person attributed the delay to negotiations between top executives of UBS's investment bank and its board over the size of the bonus pool, the WSJ reported.

The bank is announcing results next week. Activist investors failed to reject UBS's 2009 bonus plan at last April's shareholder meeting.

Losses at the investment bank in 2008 were 34 billion Swiss francs ($36.2 billion), forcing the Swiss government to bail it out.

UBS has worked to rebuild the investment bank run by Carsten Kengeter, whose 13.9 million franc bonus for 2009 was unpopular in Switzerland when the bank reported a net loss in the same year. Chief Executive Oswald Grubel declined a bonus in 2009.