i dont quite get what your fishing for here? are you planning on starting a lending business/bank? or borrowing for yourself? or somthing else.
a
fair return in this game is 0, noone looses that way. im happy to loose a bit (not 50+% per hunt though
) since this is a past time. if you are comparing with real life, genuine investments, 5%
a year is a good bank rate, so thats reasonable return on any investment (and all rl investments will bench themselves against the prevailling interest rate). taking account costs of bring in money and repatriating it, you might want to be getting 10-12%. for something more speculative, 20% maybe? now if you mean to earn a rl living in
EU then your return needs to be much higher but really depends on where you live. someone in India can live on a lot less than someeon in Germany.
so
fair is relative and subjective.