American Express Co. has ended another round of litigation with a rival card company, but still faces serious headwinds from its customers.

After announcing Wednesday that it would be getting $1.8 billion from MasterCard Inc. in settlement of an antitrust suit, the credit card lender – known for catering to jet-setters and the well-heeled – revealed that it has again underestimated how quickly its cardholders were falling behind on their debt.

“Business conditions continue to weaken in the U.S. and so far this month we have seen credit indicators deteriorate beyond our expectations,” AmEx Chief Executive Kenneth Chenault said in a statement.

MasterCard shares rose $9.42, or 3.4 percent, to $289.79 Wednesday. American Express had accused the Purchase, N.Y.-based credit and debit card processor of conspiring to discourage some banks from issuing its credit cards.