Luxfer Holdings, a global materials firm specializing in aluminum, magnesium, and zirconium, postponed its IPO on Wednesday because of poor market conditions. The Salford, United Kingdom-based company was founded in 1996 and booked $486.1 million in sales for the 12 months ended 9/30/11. Jefferies & Co. and Credit Suisse were set to be the lead underwriters on the deal.