Polysynth charges a 2% annual management fee on its DOVs i.e. ~ 0.038% per week. So, if your friend has deposited $100,000 for 1 week, the management fees generated would be $38, of which you will get $9.5. These are just weekly rewards, even assuming there is no auto-compounding of $100,000, you will still earn $494 over a year.