Trendy clothing producer Quiksilver Inc on Wednesday posted a double-digit jump in third quarter net profit as it was boosted by a sharp rise in revenue on the back of a big increase in sales through holiday bookings. The California-based firm, whose brands include Roxy, Raisins and Radio Fiji, reported net earnings for the quarter ended July 31 of $11.9 million, or 21 cents per share, compared to a profit of $8.8m, or 18 cents per share, in the year-ago period.