As a traditional, 70-year-old mortgage banking enterprise owned by a Midwest insurance company, Principal Residential Mortgage moved to the Internet as a source of new business at a deliberate pace. It wasn’t until the middle of 2001 that Principal Residential launched an online site for taking wholesale business over the Internet. But volume in that program soared to $13.7 billion by the end of the year, and surged to $22.7 billion in 2002