Shares of McDermott International (MDR) - Get Report soared 69% to $2.67  Friday after the engineering and construction company said it had received unsolicited interest to acquire all or part of Lummus Technology, which has been valued at $2.5 billion.

McDermott's Lummus Technology is a licensor of proprietary petrochemicals, refining, gasification and gas processing technologies, and supplies proprietary catalysts and related engineering.

McDermott said it has retained Evercore, a New York-based investment banking advisory firm, to help on strategic alternatives.

"The process of exploring strategic alternatives is part of our ongoing efforts intended to improve McDermott's capital structure, and we plan to use the proceeds from any transaction involving Lummus Technology to strengthen our balance sheet," David Dickson, president and CEO, said in a statement. "While Lummus is an important business within McDermott, we have decided to undertake a process to fully realize its strategic and financial value."

The Houston-based company has been pummeled by investors since Wednesday following a report that McDermott had engaged the turnaround consultancy Alix Partners of New York.

Alix Partners has advised on some of the largest Chapter 11 reorganizations, including General Motors, Kmart, and Enron. Wednesday's selloff was so fast that trading in McDermott shares was halted twice before 10 a.m. ET and the stock finished down 63% at $2.16. The low for the day was $1.44, down 76%.

Shares continued to fall on Thursday.

McDermott had long-term debt of $3.39 billion as of June 30. In July, the company updated its full-year outlook to show a net loss of $310 million on revenue of $9.5 billion. Its previous outlook had been a profit of about $170 million on revenue of $10 billion.

Separately, McDermott's previously announced efforts to sell the remaining portion of its pipe fabrication business and its industrial storage tank business are ongoing.