Fannie Mae has changed the way it computes credit loss ratio, a measure of the quality of its loans.
Bigger numbers are bad, and under the new scheme, the number is 4 basis points, but under the old scheme, it would have been 7½ basis points.
I believe that Fannie is the 2nd biggest issuer of debt in the world, and the fact that the quality of their loan portfolio is almost twice as bad as their numbers suggest is scary.