Fannie Mae’s gross mortgage portfolio fell at a compound annualized rate of 4% in August, according to the government sponsored enterprise’s monthly summary report. During August, the conventional single-family delinquency rate fell 5 basis points to 4.03%, while the multifamily seriously delinquency rate dropped 2 bps to 0.43%. Fannie completed 23,779 loan modifications in August, bringing its eight-month total to 142,698 loan mods. By the end of the month, the company held $16.6 billion in agency, non-Fannie mortgage securities, as well as $ 77.6 billion in nonagency MBS. Including its own mortgage portfolio, the company owns or backs $725.4 billion worth of American home loans. Write to Kerri Panchuk.