Blackstone p.e.-owned, London-based Clarion (now responsible for 180 exhibitions and conferences in more than 50 countries) extends its global footprint by acquiring the family-owned, Oklahoma-based Pennwell ($170m revenue) whose portfolio of events and media includes the Power-Gen series. Penwell started out more than 100 years ago with the launch of Oil & Gas Journal, which is still published weekly alongside 150 other print and online magazines, web services and newsletters, and 25 exhibitions and conferences. The acquisition almost doubles the Clarion turnover to some £300m. Is Blackstone limbering up for global leadership with a bid for Reed Exhibitions (RELX)?