When Asda relaunched its sharesave plan in February 2010, staff who had previously benefited from it were used to boost take-up.

Laura Wilcock, shares manager at Asda, said: "We asked staff to put stories about how they spent money from previous schemes on our intranet site, The Green Room. We had photos of people on holiday and at their wedding, things they had used the money for. The challenge is getting the message out there, so we use real stories to help us."

The Green Room site also includes an employee Facebook group that reminded staff of the scheme's deadline dates and invitation period. Iain Wilson, client relationship director at Computershare Plan Managers, which administers the scheme, says: "There was evidence that that group had a viral effect in the broader Asda community.

"What was great about using that, apart from it being very cost-effective, was that you can get things done really quickly. If there is evidence that a key message has not been absorbed properly, you are able to correct that in seconds."

The scheme, which last year had 25,000 UK members, allows staff to save £5 to £250 a month over three years. The shares are those of Asda's parent company, Wal-Mart, which is listed on the New York stock exchange.

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