NEW YORK (CNN/Money) - Adelphia Communications said Thursday that it expects to restate its financial results for three years to reflect $1.6 billion in off-the-books debt, and that it continues to review its accounting methods.

The news comes a month after the Securities and Exchange Commission said it is investigating Adelphia and $2.3 billion in loans obtained by the Rigas family, which controls the company, that were secured off the books by Adelphia, the New York Times reported on April 4.

The way that debt was recorded could have implications for the company, its shareholders and debtholders if the Rigas family, which owns about 60 million Adelphia shares, or about 24 percent of the company, defaults on the loans, the Times said.

Adelphia's (ADLAE: down $0.30 to $6.65, Research, Estimates) shares sank 7.3 percent in midday trading Thursday. The stock is down 46 percent since April 3, the day the SEC announced its investigation.

The nation's sixth-largest cable television provider, based in Coudersport, Pa., said in a statement Thursday that it has tentatively concluded that it should reflect $1.6 billion worth of "borrowings and related interest expense" incurred by the Rigas family as liabilities in its financial statements.

The company was not immediately available for comment Thursday.

Adelphia said the changes are subject to the completion of its annual audit by Deloitte & Touche LLP.

Adelphia said recently that the delay in filing its annual report for 2001 could force it to default on certain credit agreements.

A week before the SEC unveiled its probe, Adelphia admitted that Highland Holdings, a partnership owned by the Rigas family, borrowed money against credit facilities co-guaranteed by Adelphia. Some of the money was used by Highland to buy more shares of Adelphia.