The demand curve for these entities becomes nearly horizontal near the equilibrium of the floor model, unlike in the corridor model. The demand curve for these entities is a downward-sloping logistic curve with bounds of i-sub-r and i-sub-b, which intersects their vertical supply curve. A simple expression for the money multiplier is the reciprocal of a ratio named for these entities, whose excess sometimes has a negative interest rate (15[1])to encourage lending. (*) Open market operations traditionally change the quantity of these entities, which is often graphed against the interest rate. A minimum requirement for the size of these entities, often expressed as a percentage of liabilities, forms a system named for their “fractional” variety. For 10 points, name these deposits made by banks to the central bank. ■END■ (0[2])