The first thing you need to do is talk to your loan officer and accountant to determine your total interest cost, net of the tax benefit, which will tell you how much your investment portfolio needs to earn in order to pay off the interest-rate charges of your mortgage.

FORBES: Burdening Your Retirement With A Mortgage

In net interest margin (interest income minus interest cost, divided by the loan total), Lewis' bank scores 2.6%, versus 2.4% for Citi and 2.3% for Chase.

FORBES: Money For The Masses