So far, 300 high risk lines including electrical goods, print cartridges, sports equipment, men's grooming equipment, jewellery, sunglasses, cosmetics and ambient and some fresh items are being tagged.
Early results show this has improved on-shelf availability of one type of razor blades 10% to over 80%, compared to 70% for a similar untagged line.
One jewellery supplier has seen 79% of its normal year's sales in the four months since its jewellery was Electronic Article Surveillance (EAS) source-tagged due to more open merchandising.
Asda started asking suppliers to put security tags in packaging this year in a bid to reduce shrinkage by 30%. It set up the EAS system in partnership with ADT Fire and Security.
Wal-Mart's Retail Link system is used to identify lines with a high level of shrinkage and potential shrinkage figures are used to decide whether lines should be EAS source tagged.