Standard & Poor’s continued to rake in the most rating business in the burgeoning non-agency MBS market through the first nine months of 2005, but the company is seeing increased competition from an old rival and a newcomer in the market. S&P rated some $802.10 billion of non-agency MBS during the first three quarters of the year, or about 93.4 percent of the rated volume of new issuance. That included...