Nortel Networks (NT) was down 4.3% in midmorning after CEO John Roth announced he will retire next year and COO Clarence Chandran, already on medical leave, decided to quit. The telecommunications equipment maker said it has begun to search for a new CEO.

In addition, the company told


Thursday that it plans to exit the DSL business to focus on higher-growth markets. The company was a relatively small player in the DSL market.