Swiss banking heavyweight Credit Suisse says it will reduce its global bonus pool by 5 percent to pay for a new British tax on bonuses, but will cut deeper into the bonuses for its top managers in Britain.

"The global Credit Suisse bonus pool will be reduced by 5 percent," said spokesman Andres Luther

In addition, the bonuses of its 400 managing directors in Britain will be cut by 30 percent, he said.

Credit Suisse is the first major bank to disclose how it is going to handle a one-time 50 percent tax on bankers' bonuses whose details were unveiled last month.

Germany's Deutsche Bank said earlier this week it would spread the cost of the tax among its staff but did not indicate how precisely it was going to do that.

Credit Suisse is due to report full-year results on Feb. 11.

Switzerland's finance minister has rejected the idea of introducing a U.K.-style tax on bankers' bonuses.