Cor Boonstra has stepped down from the supervisory board of Dutch retailing group Koninklijke Ahold , according to newspaper Het Financieele Dagblad . The resignation followed news that the former Philips chief had traded around NLG 700,000 (US$288,600) Ahold shares during a "closed period" in August 2000, before the company's quarterly earnings were released. He also failed to report the sale.