how the empirical rate becomes the risk-free rate

theres never any reason for a committee to set rates

extend the minimal bivector transaction json with item, debitor_approval_time, creditor_approval_time fields:

{
  "debitor": "john",
  "creditor": "mary",
  "price": "1.00",
  "quantity": "1",
  "item": "bottled water",
  "debitor_approval_time": "2026-05-16T12:00:05Z",
  "creditor_approval_time": "2026-05-16T12:00:00Z"
}

the bivector transaction records number ownership as moving in the debitor → creditor direction with goods & services (item) ownership moving in the opposite direction

now stream every settled bivector and contract them with sum credit / sum debit - 1 per account

then average across accounts

SELECT AVG((revenue - expense) / expense) * 100 AS risk_free_rate
FROM margin_per_account
WHERE expense > 0;

the percentage that returns is the risk-free rate