The ayllu
a styel of Andean village association
Graeber / Wengrow 423: "One of the ayllu's main functions was to redistribute agricultural land as families grew larger or smaller, to ensure none grew richer than any other"
"records were kept and at the end of each year all outstanding credits and debts were to be cancelled out"
use of the khipu
"Each allyu appears to have had its own khipu strings, which were constantly knotted and re-knotted to keep track as debts were registered or canceled out. It's possible that khipu were invented for such purposes"
even under later Inca rule, "the pre-existing ayllu system continued to provide social security"