Adidas, the German sportswear company, suffered a disappointing 64% drop in net income in the last three months of 2009 from a year earlier.

The company said its fourth quarter net income was 19m euros ($26m; £17m), down from 54m euros in 2008.

Adidas said the results were hit by the strengthening of the euro last year and rising costs.

The results caught markets by surprise, with Adidas’s share price falling 5% to below 36 euros when trading began.

Total sales in the fourth quarter were 2.458bn euros, down 5% from a year earlier. Some of the loss was attributable to the strengthening of the euro during 2009, which reduced the reported value in euros of sales outside the eurozone.

However, even adjusting for this currency effect, sales in the important North America market fell 7% from a year earlier, and worldwide sales overall registered little growth.

Adidas also recorded 33m euros of write-downs on Chinese distribution rights of its subsidiary Reebok and on its stores.

The figures rounded off a difficult year for Adidas in which full-year net income fell 62% to 245m euros.