Shares of Protalix BioTherapeutics soared in trading in New York and Tel Aviv Tuesday on reports that the company is preparing for a possible $1 billion sale. Late Tuesday the Carmiel-based company confirmed a critical aspect of the rumor, saying it had retained the U.S. investment banking arm of Citigroup to review a range of strategic alternatives. “The company has engaged Citigroup to assist it in reviewing a broad array of product partnering, technology sharing and other strategic alternatives. There is no assurance that Protalix will undertake any such strategic alternative,” the company said, insisting that it would not provide any further details for now. On Monday, before the reports began circulating, the company was trading at a Tel Aviv Stock Exchange market capitalization of NIS 1.7 billion, or $460 million. In TASE trading Tuesday, Protalix shares jumped more than 19% to NIS 22.60 each, giving it a market cap of NIS 2.05 billion. The rise was also seen on the New York Stock Exchange, where shares were up 15.9% at $6.21 as of midafternoon. Industry sources said Tuesday that Protalix’s board aims to sell the company for at least a 50% premium to the Monday market cap, or about $750 million. Other reports put the sale price at more than $1 billion. Protalix’s asset is its ProCellEx technology, a plant-cell-based protein expression system based on research by Dr. Yosef Shaltiel that makes use of genetically engineered carrot cells.