European stocks declined the most in two weeks as investors bet that the rally in the Stoxx Europe 600 Index to a 15-month high overshot the economic outlook and prospects for corporate earnings.

German investor confidence rose for the first time in five months in September, a report showed today.

The ZEW Center for European Economic Research in Mannheim said its index of investor and analyst expectations, which aims to predict economic developments six months in advance, climbed to minus 18.2 from minus 25.5 in August. Economists forecast a gain to minus 20.

National benchmark indexes fell in 15 of the 18 western European markets. Germany’s DAX slid 0.8 percent, while the U.K.’s FTSE 100 lost 0.4 percent. France’s CAC 40 dropped 1.2 percent.

Akzo Nobel dropped 5.5 percent to 46.16 euros, the biggest decline since September 2011. Buechner will take leave for one month to recuperate from fatigue on the advice of his doctor, Amsterdam-based Akzo said. He plans to return in the first half of October and Chief Financial Officer Keith Nichols will be the point-person in the interim period.

Aviva lost 4 percent to 344.9 pence. Deutsche Bank AG downgraded the stock to hold from buy and Bank of America Corp. cut its rating to underperform, the equivalent of sell, from neutral.