Rossignol, a French ski-maker, was bought by Altor, a Swedish private-equity firm. The global ski market has gone downhill from its peak in the 1980s partly because more people are renting skis rather than buying them.|| The Nordic firm hopes to make Rossignol more profitable by expanding into outdoor wear, a strategy it tried with Helly Hansen, a Norwegian sports-apparel firm that had struggled before Altor bought it in 2006.||