The dramatic expansion of the credit box for loans sold to Fannie Mae and Freddie Mac in the first quarter of this year held steady in the second quarter, according to a new Inside Mortgage Trends analysis of mortgage-backed securities data. In the first quarter, the share of purchase loans sold to the government-sponsored enterprises with credit scores ranging from 620 to 699 jumped by nearly 7 percentage points to 21.4 percent. The low-score share ... [Includes one data chart]