Banks with significant portfolio capacity continue to stock up on mortgages because they offer strong returns and can help efforts to cross-sell other products. While most of the mortgages being added to portfolios are jumbos, in some instances banks are retaining conventional mortgages. JPMorgan Chase reported that it added mortgages with a balance of $19.0 billion to its portfolio holdings during the second quarter of 2015. Marianne Lake, chief financial officer at the bank ...