what we're going to do in this video is think about monetary policy which is policy that a central bank can use to affect the economy in some way this is often contrasted with fiscal policy and that would be a government deciding to tax or spend in some way in order to make adjustments to an economy but to help us think through monetary policy let's bring up our model for the money market and just as a little bit of a review here on the horizontal axis i have the quantity of money unless we could imagine that say the m1 which is cash in circulation and checkable deposits and then here in the vertical axis we have our nominal interest rate in this model we have assumed a perfectly inelastic money supply that's why we have this vertical line which isn't exactly how the world works but we'll go with that for the sake of this video and then we have the demand curve for money at high nominal interest rates the cost the opportunity cost of keeping cash is very high so people would not want to keep much of it around and then when nominal interest rates are low the opportunity cost or at least the perceived opportunity cost of holding cash is a lot lower so people might want to hold more of it and so you have a higher demand for money and this point where the supply and the demand intersect we have seen this before this point of equilibrium we see that that would result in our equilibrium nominal interest rate but let's say this is the world that we are in and we are in a recessionary or a negative output gap and you are the central bank of this country what could you do well in general you say well it would be nice if interest rates if nominal interest rates were lower then maybe people would be willing to borrow more there'd be more of a demand for money and they would use that money in order to make investments or in order to consume more and we could close that recessionary gap but how would you lower interest rates well one way would be to increase the money supply if we could shift this vertical line to the right somehow but how would you do that we often talk about central banks printing money but how do they get that money actually into circulation how do they actually increase the money supply well there's a couple of tools at their disposal one is the idea of open market operations open market operations and this is the tool that central banks most typically use let's say that this is a bond that i currently own and a bond is a loan to some entity and this paper says hey that entity is going to pay you back with interest at some point in the future and let's say this is a government bond let's say it's to the u.s government what it what the federal reserve might do in the united states the central bank and this is how most central banks work the federal reserve says hey i want to increase the money supply and so they say hey i'm going to go into the open market and buy a bond so i might not know who's buying that bond but it happens to be the federal reserve and so instead of selling it to someone else who would who would give me cash that's already in circulation the federal reserve would be introducing new cash into circulation this might be money that they just printed and i'll say printed in quotes because there's not a lot of physical cash or at least as much as there used to be these could just be digital numbers in banking accounts at certain places but it has the same functional idea that this is part of the monetary base and then we've talked about this before you have a money multiplier i would put this into a bank the bank would loan out a proportion of that based on the reserve requirements and then whoever gets that would deposit in a bank and then that bank could loan out a certain proportion let's say that the central bank bought this from me for one thousand one thousand dollars and let's say that our current reserve requirement is equal to twelve point five percent well the effect on the money supply over here won't just be one thousand dollars instead we would move a thousand dollars times the money multiplier and so this would be equal to so we would have one thousand dollars and what's the multiplier going to be well it's going to be one over twelve point five percent zero point one two five one over zero point one two five this right over here is eight so the money multiplier here is eight so the effect of buying that thousand dollar bond with new printed currency so to speak printed cash so to speak would actually be to increase the money supply by eight thousand dollars eight thousand dollar increase in money supply and obviously eight thousand dollars is not going to make a big deal to an economy like the united states but imagine if this was 100 billion dollars well then this would be 800 billion dollars right over here and what would happen to this curve well it would move over let's say it moves over here and so this is money supply curve 2 and then this is m2 and now what is our equilibrium interest rate well our equilibrium interest rate our nominal interest rate has now gone down r2 and this would hopefully have the effect that the central bank wants that hey now that nominal interest rates have gone down people might borrow more for more consumption for more investment and close that negative output gap and it can work the other way as well imagine if in this situation right over here we were in an inflationary output gap a positive output gap the economy was overheating in some way and the central bank wanted to cool things down well the way they could do is they could say well if interest rates were a little bit higher that might slow things down there might be less consumption less investment how would they do that well instead of what they did here where they bought bonds to inject cash they could do the opposite they could take bonds that the central bank has and they could sell those bonds and then that would take cash out of the system by taking that cash out of the system it would take reserves out of the system and it would have the opposite effect and it would shift the money supply to the left and then you would have the effect of raising rates now another way of shifting the money supply to the right or the left here increasing or decreasing it is by changing the actual reserve requirement this is done less frequently than the open market operations but we'll see that that could have the same effect if the central bank which can set the reserve requirement were to change it from 12 and a half percent and were to instead make it let's say ten percent well then the money multiplier money multiplier when we've done the math in other videos it would go from one over twelve point five percent it would go from eight to one over ten percent to ten so the existing reserves instead of having an eight times multiplier on them you would have a ten times multiplier on them and once again that would have the effect of increasing the money supply now another tool that's sometimes associated with monetary policy is setting the discount rate now the discount window at the federal reserve in the united states isn't used in situations to affect monetary policy so much as really being a mechanism of of safety for our financial system so if a bank is running out of reserves and so they can still hold up their commitments to folks they can go to the discount window of the federal reserve and borrow money directly from the fed and the federal reserve can set this discount rate but it really becomes operational during emergencies when you hear about the federal reserve setting the rate they're really talking about the federal funds rate federal funds and this is the rate at which banks lend reserves to each other overnight and the banks are going to be lending to each other at slightly different rates but what the federal reserve the central bank will do is they'll set a target federal funds rate so what they will do is they will target a federal funds rate and typically use open market operations to make that target a reality now the last thing i want you to appreciate in this discussion of monetary policy the things that the federal reserve can do to increase or decrease the money supply to decrease or increase nominal interest rates is to think about how quickly these things might happen and how quickly their effects might be there's oftentimes a lag here it might take a little time for the central bank to realize hey it looks like we're in an inflationary situation maybe we got to decrease the money supply a little bit maybe we got to take a little bit of reserves out of the system or the other way around to realize that they're in a recession so there's usually a lag there and then even once they act they enact this monetary policy it takes time for it to fully impact the system it takes time for the interest rates to truly come down and even more once the interest rates are down it might take time for people to realize that hey maybe i want to borrow now and what would i use that money for and that for that to actually impact the economy