"It is possible that we will amend the complaint," SEC Associate Director of Enforcement Lawrence West told Reuters.
"Normally it would be to expand it in terms of charges against the same defendant or possibly to add defendants. ... I don't have any particular idea how it would be amended."
Italian prosecutors on Tuesday continued probing Parmalat in what has become Europe's largest corporate scandal in years, leading to arrests of several executives.
US securities regulators on December 29 charged Parmalat with securities fraud, accusing it of "one of the largest and most brazen corporate financial frauds in history" related to an offering of about $100 million in unsecured debt.
"We are definitely investigating all possibilities, all activities in the United States," said West, who returned in recent days from Italy where he met with Italian officials, including prosecutors and officials from the Italian stock market regulator, Consob. "I met with no Parmalat officials," he said.
Asked about the possible involvement of US banks in transactions with Parmalat, West said, "I won't address those specifically. I'll just say we're addressing all aspects."