Shares of McDermott International Inc. plummeted 49% in morning trading Wednesday, prior to a trading halt for news pending as of 10:57 a.m. Eastern. Volume had swelled to 17.9 million shares, compared with the full-day average of 7.5 million shares, prior to the halt. The provider of construction, engineering and technology services to the energy industry was not immediately available for comment. The stock was halted once for volatility at 10:50 a.m. and again at 10:57 a.m., the same time as the halt for new. The stock was the leading loser listed on the NYSE, and was headed for the biggest one-day decline since the company went pubic in 1982 prior to the trading halt for news. On Tuesday, the company said its Qingdao McDermott Wuchuan Offshore Engineering Co. Ltd. joint venture in China was awarded a contract between $50 million to $250 million to provide modules for the Arctic LNG 2 Project in Russia. The stock has now plunged 54.1% year to date prior to the halt, while the SPDR Energy Select Sector ETF has gained 7.9% and the S&P 500 /zigman2/quotes/210599714/realtime SPX +0.74% has rallied 19.6%.