As lawmakers scramble to cut a budget deal and avoid defaulting on U.S. debt, the head of a top Chinese rating agency claims it's too late.

Guan Jianzhong, president of Dagong Global Credit Rating Co. Ltd., reportedly told state media that the United States has already defaulted by letting the U.S. dollar weaken.

"In our opinion, the United States has already been defaulting," Guan was quoted as saying, according to AFP...