(Telecompaper) Liberty Global has increased its stake in Dutch cable operator Ziggo to 15.0 percent, according to a filing with the Dutch securities regulator AFM. Liberty Global first acquired a 12.65 percent stake in Ziggo at the end of March, after Ziggo's shareholders placed a large stake on the market and Barclays was unable to find investors for the shares. The shareholders Cinven and Wrburg Pincus sold the week prior to Liberty's latest announcement their remaining shares in Ziggo, in a discounted one-day offering. Liberty Global, which already owns the second-largest cable operator in the Netherlands UPC, said it considers the Ziggo stake a strategic investment.