Bank holdings of MBS have increased significantly this year, with the growth concentrated among large banks. Industry analysts suggest that large banks have increased their MBS holdings due to capital requirements, and demand is expected to persist for months to come, pushing up MBS prices. The 25 largest banks held a combined $1.15 trillion in MBS as of the end of June, according to an Inside MBS & ABS analysis of data from the Federal Reserve. The holdings increased by $63.90 billion compared with the end of 2014 and coincide with an increase in deposits at banks. “MBS performance so far this year owes...