NY -- Standard&Poor's CreditWire 10/2/96 -- Standard&Poor's today has raised its ratings on Calpine Corp.'s $180 million senior unsecured notes due 2006 and $105 million senior unsecured notes due 2004 to single-`B'-plus from single-`B'. The corporate credit rating is single-`B'-plus. The upgrade is a result of Calpine's successful completion of the sale of 18 million shares of common stock in an initial public offering, which yielded an additional $83 million in net equity to Calpine's balance sheet. This more than doubles the amount that was previously outstanding. As of June 30, 1996, Calpine had equity of $80 million with a corporate debt to capitalization ratio of 78%. The additional equity on a pro forma basis reduces