If spot ETFs hold bitcoin directly and charge fees, why do prices of different ETFs diverge over time?
e.g. i'm dividing FBTC by IBIT 
Discussion
If you go by closing prices, they're all pretty much in parallel.
How were you able to see closing prices only?
Seeking Alpha uses daily closing prices in their charts.
It doesn’t seem to let you divide one chart by another
Are you trying to do a mathematical comparison for research purposes, or just checking to see how well they follow each other? 