US retail giant Wal-Mart has made details of its annual bonus for store employees public for the first time in 20 years.

The retailer announced that some US$0.5bn would be split between 80% of its hourly store staff, giving an average payout of around US$651 per person. Payments will vary according to certain criteria, principally whether the employee's store had met profit and sales targets for the year and whether the employee is full-time or part-time.

Wal-Mart rebuffed suggestions that it was making details of the bonus public in response to criticism from unions about pay and conditions at the company. The retailer said it was making the announcement to honour its employees.