Among Mortgage SpecialistsInternet banks have yet to prove their long-term viability but DeepGreen Bank turned in a gaudy 25.01 percent return on assets during the first quarter of 2004, making it the most profitable in institution with over half of its assets in mortgages or MBS. Virtually all of the company’s revenue came from the sale of its online home-equity lending platform and other assets to Lightyear Capital.