Shares in Natixis suffered their biggest one-day fall since the French investment banking and asset management joint venture's listing three months ago, as fears over its exposure to US subprime mortgage lending overshadowed a one-fifth rise in full-year net profits.

Profits at Natixis surged more than a fifth to €2.1bn ($2.8bn) in 2006 as revenues rose across its businesses, but the figures failed to dispel concern among investors as the price of the bank's shares dropped nearly 7% to €17.67 by 10:10 GMT from yesterday's €18.95 close.