A PT (principal token) from
@ExponentFinance, like
@onrefinance's PT-ONyc, redeems for $1 of ONyc on its maturity date.
Before maturity, a PT's market price moves with demand for fixed yield
Kamino values PT collateral from a set yearly discount that shrinks in a straight line to $1 at maturity, and is not valued by the market price
Market swings leave your borrowing limit unchanged, so you know exactly how your collateral value and LTV will move until maturity