DESPITE ITS POSITION as the No. 1 operator in the European express market and the world’s second-largest logistics provider, the recent boom in the logistics sector hasn’t shaken speculation that former Dutch mail monopoly TNT is a potential takeover target. It has achieved solid growth during the past four years, but still lacks the heft of industry giants such as FedEx Corp. or Deutsche Post AG and has been distracted by an investigation into tax liabilities.