There are quite a few, a pede posted a link below.
But, the issue will always remain, how do you assay or verify the holdings? This is no different than having a bunch of gold stored in a centralized location with paper saying 'yeap, we have this amount of Gold in store'.
There are quite a few, a pede posted a link below.
But, the issue will always remain, how do you assay or verify the holdings? This is no different than having a bunch of gold stored in a centralized location with paper saying 'yeap, we have this amount of Gold in store'.