Dutch retail giant Ahold has said that the US Securities and Exchange Commission has launched an inquiry into accounting irregularities at Ahold and its US Foodservice unit.

The retailer revealed on Monday that accounting irregularities led to operating earnings for 2001 and 2002 being overstated by a total of at least US$500m. Ahold also announced the resignation of its CEO and CFO.

Since the announcement, Ahold’s share price has lost around 70% of its value, sparking some US law firms to file lawsuits on behalf of shareholders who have lost money during the collapse. Ahold has declined to comment on the lawsuits.

Meanwhile, the Dutch stock-market watchdog Autoriteit Financiele Markten (AFM) said it is looking into the issues surrounding the accounting irregularities following the collapse of Ahold’s stock.

However, the AFM said it was not conducting a formal investigation. “It’s logical that the AFM looks at stocks such as Ahold given the price developments,” spokesman Seger Pijnenburg was quoted by Dow Jones News as saying.

In a separate investigation, Pan-European bourse operator Euronext said it is looking into whether Ahold had complied with rules on the timely disclosure of information, reported Reuters.