Offer your thoughts or opinion on the input financial query or topic using your financial background.

How to reduce mortgage rate with low income but high assets
In your shoes, I would  pay off the mortgage with the after tax investments and be done. You have different goals than I do in that you want to keep the debt.  So, I would  start calling mortgage brokers and asking for someone who does "manual underwriting".    Manual underwriting essentially means they use common sense and look at your situation for what it is instead of saying "income=10K means disapprove mortgage".   It may be that your situation is different enough from mortgage guidelines that you can't now get a conforming mortgage (i.e. one that is readily re-sellable to another mortgage holder).   If that is the case, you can look for a small bank or credit union that would be interested in adding your loan to their portfolio and not reselling it.