(ShareCast News) - Mall owner Hammerson said returns on its property investments were up 5.7% for the first half of the year, 1% higher than estimated.The retail property investor said returns for the six months ended 30 June 2015 were up due to strong returns premium outlets and developments.Hammerson, which owns more than 50 retail centres, said improving consumer confidence and positioning of its UK shopping centres boosted growth in sales of 2%.Net rental income was up 8.6% to £159.5m from £146.9m, but profit before tax was down 9.2% from £362.9m to £329.4m compared with the first half of last year.The profit dip reflected a reduction in profit revaluations which boosted earnings in the same period last year.Hammerson increased its first half dividend to 9.5p from 8.8p.Chief executive David Atkins said the business was on track to open four new malls in 2015."The business has performed very well in the first half, underpinned by robust consumer confidence and an active asset management strategy resulting in sector-beating earnings growth of 13%," Atkins said.