The world's largest producer of athletic shoes, Yue Yuen Industrial Holdings Ltd, on Tuesday announced a 39 per cent surge in third quarter net profit as it was boosted by solid back-to-school orders. The company, which makes footwear for industry giants including Nike, Adidas and Reebok, posted a net profit for the 13 weeks ended June 30 of $87.4 million versus $63m in the year-ago quarter.