Mortgage securitization activity rose smartly in the second quarter of 2005, with an estimated $523.47 billion of new MBS issued during the period, according to a new market analysis by Inside MBS & ABS. Issuance during the second quarter was the highest three-month volume since the second quarter of 2004, when $537.51 billion of new MBS were issued. Since then, new MBS production levels had steadily declined, hitting $441.25 billion during the first thee months…