What types of mortgages are most likely to default? A new study by Countrywide Financial turned up some interesting results. The study, which was presented at this week’s American Securitization Forum Conference by Chief Credit Officer John McMurray, looked at the characteristics of some 70 million first lien mortgages originated between 2000 and 2005. The idea was to look at the way that a variety of different loan variables, including FICO score, combined LTV,…