Anyone doubting the importance of interest-only loans in the subprime market should look no further than the securitization market, where they appeared in record numbers during the first half of the year. According to data compiled by affiliated newsletter Inside MBS & ABS, $46.2 billion in loans with interest-only features were securitized through the end of June. That marked a 5.9 percent increase from 2004, when $43.6 billion in IO loans were included in… [One data table included]