Latest / Monetary Policy Explained with Fexingo: Central Banks, Money Supply, and Interest Rates / How Central Banks Use Reverse Repos to Drain Liquidity
Transcript
- Lucas: So there's this operation the Federal Reserve runs every single business day — it starts just after 9:00 AM Eastern, and it effectively takes money out of the banking system. It's called the overnight reverse repurchase agreement facility, or reverse repo for short. Luna: And this is the one that hit almost two and a half trillion dollars at its peak in 2023, right? I remember seeing that number and thinking, why would the Fed be pulling that much cash out of the system when it was still supposedly tightening? Lucas: Exactly — that's the counterintuitive part. We usually think of the Fed as lowering rates to stimulate or raising rates to cool down. The reverse repo facility isn't about changing the rate target itself. It's about making sure that the actual overnight rate — the one banks charge each other for reserves — stays right where the Fed wants it. Lucas: Think of it this way. After the pandemic, the Fed bought trillions of dollars of Treasury bonds and mortgage-backed securities through quantitative easing. Those purchases created a huge pile of reserves sitting in bank accounts at the Fed. By mid-2024, total reserves were around three and a half trillion dollars. Even with QT, reserves are still elevated. Luna: And too many reserves can push the fed funds rate below target, because banks don't need to borrow from each other. They're flush. Lucas: Right. So the reverse repo facility gives the Fed a way to mop up some of that excess liquidity — temporarily, overnight. Here's how it works. The Fed offers to sell a Treasury security to a counterparty — typically a money market fund or a primary dealer — with an agreement to buy it back the next morning at a slightly higher price. Luna: So it's a loan secured by Treasuries, but structured as a sale and repurchase. The interest the counterparty earns is the difference between the sale price and the repurchase price. Lucas: Exactly. And the rate the Fed pays on that transaction is called the overnight reverse repo rate, or ON RRP rate. For the last couple of years, that's been set at five point three percent — right at the bottom of the fed funds target range. Because money market funds can earn that rate by parking cash at the Fed overnight, they have no incentive to lend in the private repo market at a lower rate. Lucas: And that's the key mechanism. By setting the ON RRP rate, the Fed puts a floor under short-term rates. If private market rates try to dip below that floor, money market funds just move their cash to the Fed instead. The facility effectively establishes a minimum rate for overnight money. Luna: But that only works if money market funds actually have cash to park there. During quantitative tightening, the Treasury also issues more debt, and when investors buy that debt, cash flows out of money market funds into the Treasury's general account at the Fed. Lucas: That's exactly what's been happening. The reverse repo facility peaked at around two point four trillion in June of 2023, and since then it's been declining — it's down to about three hundred billion as of June 2026. That decline tells us that the Treasury's cash management and QT are actually draining reserves from the system. Luna: So the reverse repo facility acts like a shock absorber. When there's too much cash in the system, it soaks it up. When liquidity starts to tighten, the facility balance falls naturally. Lucas: Exactly. And the Fed watches that balance closely. If the reverse repo facility drained all the way to zero, it would be a signal that reserves had become scarce, and the fed funds rate might start pushing above the target range. At that point, the Fed might need to stop QT or even resume some lending operations. Lucas: This is actually what happened in September 2019. Reserves had been draining for months, and suddenly overnight repo rates spiked to nearly ten percent. The Fed had to intervene aggressively. That's why they built the standing repo facility as a backstop. But the reverse repo facility is the first line of defense on the downside. Luna: So it's a bit like a thermostat — it doesn't heat or cool the room directly, but it keeps the temperature from drifting too far. Lucas: That's exactly the right analogy. And the counterparties matter. The Fed only deals with primary dealers and money market funds — it's not open to every bank or every hedge fund. But money market funds are huge. Even at three hundred billion, they're still parking a significant amount of cash at the Fed each night. Luna: And what about the international angle? The ECB has a similar facility, right? Its deposit facility rate effectively works as a floor on euro-area overnight rates. Lucas: Yes, the ECB's deposit facility is slightly different — it's a standing facility where banks can deposit excess reserves and earn interest. That's more like the Fed's interest on reserve balances, which also pays five point four percent right now. But the concept is similar: you give banks a place to park cash at a guaranteed rate, and that sets a floor. Lucas: The reverse repo facility is unique because it opens that floor to non-bank institutions — money market funds, which otherwise wouldn't have direct access to the Fed's balance sheet. That was a design choice after the financial crisis. The Fed wanted to control rates without relying solely on banks. Luna: Let me ask a practical question. If I'm a money market fund manager, why would I ever lend in the private repo market at five point two percent when I can get five point three from the Fed with no credit risk? Lucas: You wouldn't — unless you need the operational flexibility. Private repo can be for longer terms, or you might need specific securities as collateral. But for plain vanilla overnight cash, the Fed's rate is hard to beat. And that's exactly the point. It puts a price floor under the entire money market. Lucas: Now, there's been debate about whether the reverse repo facility distorts markets. Some critics say it pulls too much cash out of bank reserves, making banks less willing to lend. Others argue it's a necessary tool to keep the fed funds rate inside its range, especially when reserves are abundant. Luna: And the Fed seems to agree with the latter view, because they've kept the facility open and actively used it for years now. Lucas: Right. In fact, the facility became a permanent part of the Fed's toolkit in 2021. Before that, it was a temporary response to the 2008 crisis. So it's no longer just an emergency measure — it's a standard operating procedure. Lucas: And if you look at the trajectory, the declining balance since 2023 tells a story. As QT and Treasury issuance absorb reserves, the reverse repo facility acts as a buffer. Once it's gone, the Fed will have to watch reserve scarcity much more carefully. That's the moment when the debate about the optimal level of reserves will really heat up. Luna: So the reverse repo facility is essentially the Fed's way of fine-tuning liquidity without actually buying or selling bonds day to day. It's elegant in its simplicity. Lucas: It really is. And it's one of those tools that most people never hear about, but it's quietly running every single morning, keeping the plumbing of the financial system working. Lucas: You know, walking through the economy with us — understanding how these mechanisms actually work — that's exactly why we do this show. And it's also why we've never run ads on these episodes. We just think this kind of explanation should stand on its own, without being interrupted by a commercial. Luna: Yeah, I think listeners appreciate that. It keeps the focus on the topic, not on selling something. Lucas: Exactly. So if you find value in what we're doing and you want to support that ad-free choice, there's a simple way — just go to buy me a coffee dot com slash fexingo. No pressure, no perks, just a way to keep this going. Luna: And we mean that — no special shout-outs or anything. Just a quiet thank you from us. Lucas: Alright, back to the plumbing. One question I get a lot: what happens if the reverse repo facility runs dry? That is, if the balance drops to zero. Does that mean the Fed has lost control of rates? Luna: Not necessarily, because they still have the standing repo facility on the other side — that's the one that lends money to banks at a rate above the target range. Lucas: Right. The standing repo facility sets a ceiling. So between the reverse repo facility floor and the standing repo facility ceiling, the Fed has a corridor for the fed funds rate. The corridor is about fifty basis points wide — five point three on the bottom, five point eight on the top. Lucas: As long as both facilities are operational, the Fed can keep rates inside that corridor. The reverse repo facility is just the more active of the two — it's the one that sees actual usage. The standing repo facility is more of a backup. Luna: So the declining reverse repo balance isn't necessarily a problem. It just means the corridor is being tested from the other side. Lucas: Exactly. And the Fed has been very transparent about its plans. They've said they want to stop QT once reserves are at a level they consider 'ample' — probably somewhere around three trillion. The reverse repo balance gives them a real-time signal of how far along that process is. Luna: So it's almost like a fuel gauge for liquidity. When the reverse repo tank is empty, the Fed knows it's time to ease off QT. Lucas: Perfect analogy. And we're actually at that point now — with the facility at three hundred billion, it could hit zero within a few months if the current pace of Treasury issuance and QT continues. That would make the second half of 2026 a very interesting period for monetary policy. Luna: We'll be watching. Thanks, Lucas. Lucas: Thanks, Luna. For everyone listening, keep asking these questions. The more you understand about how the system actually works, the better you can make sense of the headlines.