The poor in countries where UBI is being considered are not currently starving. So increased spending on food would take the form of buying higher-quality food. The resources for making higher-quality food can also be used for many other goods and services, bought by rich and poor alike. That includes investment goods, bought indirectly by the rich through stock purchases.
UBI could lead to a shift of resources from investment to current consumption, as resources are shifted from the well-off to the poor. This has economic effects, but is not clearly either good or bad. Other things being equal, this would increase interest rates, which is again neither good nor bad of itself.
However, you seem to be assuming the opposite—that UBI would lead to higher investment in stocks (presumably by the middle class?). That would reduce interest rates, not increase them. (I’m referring here to real interest rates, after accounting for inflation. Nominal interest rates could go anywhere, depending on what the central bank decides to do.)
Whether UBI harms the middle class would depend on whether they benefit on net, after accounting for the higher taxes, which could of course be levied in various ways on various groups.
Of course, a sufficiently large UBI would destroy the entire economy, as the incentive to work is destroyed, and any productive activity is heavily taxed to oblivion. But the argument in this post applies to even a small UBI, purporting to show that it would actually make the poor worse off. It wouldn’t, unless you hypothesize long-term speculative effects like “changing the culture of poor people to value hard work less”, which could exist, but apply to numerous other government programs as much or more.
The poor in countries where UBI is being considered are not currently starving. So increased spending on food would take the form of buying higher-quality food. The resources for making higher-quality food can also be used for many other goods and services, bought by rich and poor alike. That includes investment goods, bought indirectly by the rich through stock purchases.
UBI could lead to a shift of resources from investment to current consumption, as resources are shifted from the well-off to the poor. This has economic effects, but is not clearly either good or bad. Other things being equal, this would increase interest rates, which is again neither good nor bad of itself.
However, you seem to be assuming the opposite—that UBI would lead to higher investment in stocks (presumably by the middle class?). That would reduce interest rates, not increase them. (I’m referring here to real interest rates, after accounting for inflation. Nominal interest rates could go anywhere, depending on what the central bank decides to do.)
Whether UBI harms the middle class would depend on whether they benefit on net, after accounting for the higher taxes, which could of course be levied in various ways on various groups.
Of course, a sufficiently large UBI would destroy the entire economy, as the incentive to work is destroyed, and any productive activity is heavily taxed to oblivion. But the argument in this post applies to even a small UBI, purporting to show that it would actually make the poor worse off. It wouldn’t, unless you hypothesize long-term speculative effects like “changing the culture of poor people to value hard work less”, which could exist, but apply to numerous other government programs as much or more.