CenturyLink plans to lay off as much as 8 percent of its work force by the end of the year.

Annmarie Sartor, spokeswoman for the telephone company, said the announcement came in a companywide memo from CEO Glenn Post on Wednesday, according to the Monroe News Star website.

CenturyLink's headquarters is in Monroe, Louisiana, and the company currently has about 43,000 employees worldwide. A 7 percent to 8 percent workforce reduction would affect 3,500 people.

"We all understand the pressure caused by the decline in our legacy revenues — it creates a $600 million negative impact on our business each year. While we continue to see positive growth in our strategic products, the profit margins of these strategic products and services are considerably lower than those associated with the legacy revenue we are losing," Post wrote in the memo.

CenturyLink today fell 1.6 percent to $26.98 a share in New York. The stock is up about 7 percent this year, compared with a 5.1 percent gain for the S&P 500 stock index.

"So, while I am very confident that we will continue to accelerate our revenue growth over time, I also have reached the very difficult conclusion that the loss of higher margin legacy revenue requires that, in addition to achieving our growth targets, we must also significantly realign our fundamental cost structure," Post wrote. "It is a difficult conclusion to reach, but our long-term success requires us to adapt to the reality of the rapidly changing environment in which we are operating."