MCI liabilities could potentially lower the purchase price being offered for the company by Verizon Communications by as much as $0.21 per share, according to regulatory filings made by Verizon today.

The merger agreement between the two companies stipulates that if the estimated amount of cash needed to satisfy MCI’s bankruptcy claims and international tax liabilities—together with the amount MCI spends on those liabilities between January 1, 2005 and the closing of the merger—exceeds $1.775 billion, the difference will be subtracted from Verizon’s offer.

According to Verizon’s filing, MCI currently estimates the sum of its paid and remaining liabilities to fall between $1.615 billion and $1.845 billion. At the low end of that range, those liabilities would have no effect on Verizon’s offering price; at the high end, they could lower Verizon’s price by as much as $0.21 per share. Verizon has not yet verified MCI’s estimate.

Two of the largest components of MCI’s estimated liabilities are its international income tax liabilities, which it estimates to be $685 million, and domestic tax claims, which include administrative expense claims and could be between $585 million and $752 million.

Verizon in May offered 0.5743 shares of its common stock for every MCI share plus a cash dividend of $5.60 per share, for a total purchase price of about $26 s share or about $8.4 billion.