U.S. Bank is suing Countrywide Financial Corp. — now owned by Bank of America (BAC) — for allegedly breaching its contractual obligation to repurchase more than 4,000 toxic mortgages securitized in the HarborView Mortgage Loan Trust 2005-10. U.S. Bank, which is trustee for the HarborView Trust, filed suit in New York to compel Countrywide (now BofA) to buy back the soured loans. The suit relates to $1.75 billion in certificates sold to investors by HarborView. U.S. Bank says Countrywide originally sold the loans to Greenwich Capital Acceptance Inc., which, in turn, sold those loans to U.S. Bank National Association. With that sale, Greenwich passed on its rights, including the right to ask Countrywide to repurchase mortgages that breach representations made about loan quality in the original contract. The suit alleges Countrywide failed to buy back troubled loans that violated terms of the agreement. A Bank of America spokesperson declined to comment, saying the company is still reviewing the suit. In the complaint, U.S. Bank National says 66% of 786 loans reviewed from the trust conflict with representations made by Countrywide. The defective loans from the sample had an aggregate principal balance of $157 million. "Because of the pervasiveness and severity of these breaches, Countrywide has breached the seller representation and the trust and its beneficiaries face irreparable harm if defendants do not repurchase all of the loans as the governing agreements require," U.S. Bank National asserted. Write to: Kerri Panchuk.