question on money supply its, question, decrease, increase

gjcxc

An increase (decrease) in the money supply will result in an excess supply of (demand for) money, leaving individuals and firms to buy (sell) securities, driving securities prices up (down ) and decreasing (increasing) interest rates.
But a question about this: how does the Fed induce individuals / firms to buy (or sell) its newly issued securities if the market is already at equilibrium?

smartpants

Because market equilibrium is changed by the increase of the money supply and it now needs to find a new equilibrium point. The whole point of the monetary intervention is to move the market to some new point, not keep it at equilibrium. Of course, market equilibrium is also a theoretical idea that is not really present in real markets.