Specialty packaging company Chesapeake Corp. has filed for Chapter 11 bankruptcy protection and plans to sell itself to a group of investors for about $485 million.

The company's stock, which is traded over-the-counter, closed at 6 cents Monday, well off the $5.61 it traded at a year ago and a sharp drop from the more than $20 it traded for just a few years ago.

Chesapeake, which makes paper cartons and plastic containers for the health care, beverage and food markets, has been cutting jobs and realigning operations in an effort to foster growth and reduce costs. The company struggled earlier this year to complete a $250 million credit line with a group led by GE Commercial Finance Ltd. and General Electric Capital Corp. to refinance prior debt.

The company's shares were delisted from the New York Stock Exchange in October. Chesapeake last month reported a loss for the nine months ended Sept. 28 of $277.1 million as the company booked hefty environmental cleanup and other charges and as sales slipped to $752.5 million due to lost business with British American Tobacco and less demand for drug and health care packaging. In its 10-Q filing with the Securities and Exchange Commission, Chesapeake listed total assets of $936.6 million as of Sept. 28 and $937.1 million in total liabilities.

Chesapeake filed for bankruptcy Monday in the Eastern District of Virginia in Richmond under Chapter 11, which allows a company to reorganize. Non-U.S. units are not included in the filing.