This is the premium added to the real risk-free rate to compensate for a decrease in purchasing power over time.	Maturity risk premium	MRP
This is the premium that reflects the risk associated with changes in interest rates for a long-term security.
It is calculated by adding the inflation premium to r*.
It is based on the bonds marketability and trading frequency; the less frequently the security is traded, the higher the premium added, thus increasing the interest rate.
It is based on the bonds rating; the higher the rating, the lower the premium added, thus lowering the interest rate.
It changes over time, depending on the expected rate of return on productive assets exchanged among market participants and peoples time preferences for consumption.