Adidas has begun a search to replace its Chief Executive Herbert Hainer when his contract expires in March 2017, according to a letter Hainer sent employees Thursday, various news outlets reported.

Hainer has held the top job at the German company since 2001 and his contract was extended only last year. But he and the Adidas board have come under increasing pressure since last March, when the company issued the first of three profit warnings on the heels of disappointing sales in the United States and Russia and its golf business.

Hainer disclosed the search in a letter sent to to employees Thursday that also announced the company's plans to unveil a new five-year strategic plan in March. He said the company will look at both internal and external candidates for the job.

Adidas shares, which had fallen 24 percent in the year ended Jan. 18, rose 5.6 percent after the news on Thursday.