I don’t see the justification for donating the interest. If we think the marginal utility of the poor will fall more slowly than the interest rate, as it typically will if the poor (and others spending on them) discount the future and are aware of how much consumption they’ll have in the future, then it’s optimal to save everything including the interest, until the two are growing at the same rate.
It does :) This may also be relevant.
I don’t see the justification for donating the interest. If we think the marginal utility of the poor will fall more slowly than the interest rate, as it typically will if the poor (and others spending on them) discount the future and are aware of how much consumption they’ll have in the future, then it’s optimal to save everything including the interest, until the two are growing at the same rate.