Staff at supermarket giant Asda have saved more than half a billion pounds since a share ownership programme was launched 30 years ago. Under the savings scheme, workers set aside between £5 and £250 a month for a three-year period, at the end of which they receive a tax-free bonus and a chance to buy discounted shares in parent firm Walmart. Around 25,000 employees have joined the scheme every year, saving an average of £20 a month. Hayley Tatum, Asda\'s people director, said: \"Our in-store and depot colleagues work extremely hard, day in, day out, to serve the 18 million customers that come through our doors each week. The ShareSave scheme is just one of the ways we want to thank them for their efforts.\"