If the property sells for $500,000, the bank will get $250,000. And if it sells for more, thanks to some new clone of Alan Greenspan acting as bubblemeister, the capital gain will be split in some way. If the split is 50/50, then if the home sells for $600,000, the owner at that time will split the $100,000 further capital gain with the Savior Bank. The Savior Bank will thus make much more through its share of capital gains than it extracts in interest!