Mortgage purchase and issuance at Freddie Mac rose to $30.9bn in June, from $25.1bn in May, bringing the year-to-date total to $179bn for the first half of 2010 (HI10), according to a monthly volume summary (download here). Freddie's total mortgage portfolio decreased at an annualized rate of 0.9% in June. Total guaranteed Participation Certificates (PCs) and structured securities issued fell at an annualized rate of 0.6%. The monthly contraction in the portfolio arrives after Freddie wrapped up an initiative announced in February to purchase essentially all the single-family mortgages delinquent by 120 or more days out of its PC pools. The single-family delinquency rate decreased to 3.96% in June from 4.06% in May, and the multifamily delinquency rate fell to 0.28% from 0.32%. Refinance-loan purchase and guarantee volume was $19.1bn in June, up from $17.1bn in May. Freddie reported 21,367 modifications in June, for a total 93,558 in the first six months of 2010. The aggregate unpaid principal balance of the mortgage-related investments portfolio slipped by $8.6bn. Write to Diana Golobay.