Actually, SSA is very efficient. SSA spends just a fraction of a percentage point of the benefits it distributes on administrative costs (ie, the existence and

Actually, SSA is very efficient. SSA spends just a fraction of a percentage point of the benefits it distributes on administrative costs (ie, the existence and operation of SSA itself). But even the vast majority of that is for the means-tested SSI Title 16 program, not the simpler Title 2 SS programs. Since a UBI is much simpler than either of those, SSA could easily save even more -- there would certainly be plenty of consolidation and maybe downsizing possible after passage of UBI. But there's no reason to throw away the common infrastructure for payments that already exists.