Latest / Monetary Policy Explained with Fexingo: Central Banks, Money Supply, and Interest Rates / Why Central Banks Hold Foreign Exchange Reserves
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- Lucas: So the People's Bank of China holds well over three trillion dollars in foreign exchange reserves. That is more than the entire GDP of the UK, and it's a number that just keeps making people ask: why? Why would any central bank park that much wealth in other currencies? Luna: It does seem almost irrational at first glance. I mean, that's money they could spend on domestic priorities. Lucas: Right, and that's exactly the tension. Because on paper, reserves are just claims on other countries' assets. But they serve a very practical purpose. The most basic one is what economists call import cover. If a country suddenly can't export or can't access capital markets, it still needs to pay for essential imports like oil, food, medicine. Reserves are that buffer. Luna: So it's like an emergency fund for the whole country. How much is considered enough? Lucas: The old rule of thumb is three months of imports. That's the kind of number the IMF looks at. But for many countries, especially those with large external debts, you need more. Because if investors get spooked and pull capital out, you need dollars to settle those outflows, not just import bills. Luna: And that's where the intervention side comes in. A central bank can step into the currency market and sell dollars to support its own currency, right? Lucas: Exactly. That's the second big reason. Countries with flexible exchange rates technically don't need to intervene, but many do anyway, often quietly. Switzerland is a great example. The Swiss National Bank has amassed enormous reserves over the years, mostly to keep the franc from appreciating too sharply. A too-strong franc would crush their export sector. Luna: And a too-weak currency causes inflation and capital flight, so there's a tightrope. Lucas: Yes, and that's why reserves act as a credibility signal. When a country holds a large stock of foreign assets, it tells markets: we can defend our currency if we need to. That reduces the risk of speculative attack. It's a bit like keeping cash in your wallet to signal you can pay the bill, even if you never plan to use it. Luna: But then there's the cost. Holding reserves isn't free. You're tying up money that could earn higher returns domestically. Lucas: That's the classic 'carry cost' of reserves. If a country borrows at five percent domestically and invests in low-yielding U.S. Treasuries at two percent, it's losing money every year. That's a real trade-off. And for countries with high debt, it can be quite expensive. Luna: So why not just hold gold? We've seen some central banks buying gold recently, too. Lucas: Gold is interesting because it has no counterparty risk and it's a hedge against inflation and geopolitical shocks. But it doesn't earn interest, it's costly to store, and it's not as liquid as dollars. So central banks typically hold only a small fraction in gold. China holds about four percent of its reserves in gold, despite being one of the biggest buyers in recent years. Luna: And the dollar still dominates. Why is that? What makes the dollar so special? Lucas: It's the exorbitant privilege, as French finance minister Valéry Giscard d'Estaing called it in the 1960s. The dollar is the world's primary reserve currency, which means it's used in about 60 percent of global reserves, even though the US accounts for only about 15 percent of global GDP. That privilege means the US can borrow cheaply in its own currency, and it gives Washington enormous influence over the global financial system. Luna: But we've seen some attempts to move away from the dollar. China and Russia have talked about de-dollarization. Has that actually changed the mix? Lucas: Not dramatically. The dollar's share has declined only a few percentage points over the past two decades. The euro and the yen have their own issues, and there's no real alternative with the same depth and liquidity. The Chinese yuan is still far from being fully convertible. So the dollar remains the default, even for countries that would prefer otherwise. Luna: And that's where geopolitics comes in. Reserves can be frozen, as we saw with Russia's central bank assets in 2022. Lucas: Exactly. That was a wake-up call. Many countries now realize that holding dollars carries a political risk. If you're on the wrong side of US sanctions, those reserves could vanish. That's probably one reason why some central banks are diversifying into gold and other currencies, even if it's gradual. Luna: So it's not just about economics, it's about strategic autonomy. Lucas: Precisely. And that brings us to another angle: the sheer size of reserves in Asia. China, Japan, and India together hold over four trillion dollars in reserves. Japan's are mostly in dollars and euros, reflecting its status as a major creditor nation. India's reserves have been built up partly to cushion against capital flow volatility. Luna: And then there are the oil-exporting countries. They've been building up reserves too, especially when oil prices are high. Lucas: Right, and that's the 'resource curse' dynamic. When oil prices surge, you get a flood of dollars, which appreciates your currency and hurts other exports. So central banks often sterilize those inflows by buying foreign assets, keeping the currency from overshooting. That's what Norway does with its sovereign wealth fund, which is technically a form of reserves management. Luna: So it's a balancing act between stability and opportunity cost. And it seems like the rules are changing with the political climate. Lucas: They are, and central banks have to be more careful than ever. That's why they're looking at the composition of their reserves, not just the size. It's a complex puzzle, and it affects everything from exchange rates to the cost of borrowing for governments worldwide. Luna: If this episode has made the logic of reserves click for you, the way we keep these shows free and without ads is through listener support. If you got something useful from today, you can help us continue that by buying us a coffee at buy me a coffee dot com slash fexingo. Lucas: Yeah, and we really do appreciate that. It's what keeps us ad-free and independent. But let's get back to the mechanics, because there's a really interesting question we haven't touched yet: how do central banks actually go about buying those reserves? Do they just pick a number and start buying dollars? Luna: I'd assume there's more to it than that. Is it automated, or is there discretion? Lucas: There's a mix. For the People's Bank of China, a good chunk of dollar purchases comes from trade surpluses. Exporters earn dollars, they convert them to yuan, and the central bank ends up holding those dollars as reserves. So it's partly a byproduct of the exchange rate policy. But there's also active intervention, especially when the yuan is under pressure. Luna: And how do they decide to buy US Treasuries versus other assets? Lucas: It's a portfolio decision. They look at safety, liquidity, and yield. US Treasuries are the benchmark because they're the most liquid and considered risk-free. But some central banks have moved into other assets like agency bonds, or even equities. The Swiss National Bank famously holds billions in US stocks, which is pretty unusual. Luna: That's interesting. So reserves aren't just cash in a vault; they're a managed portfolio. Lucas: Exactly. And the management is getting more sophisticated. There are reserve managers who specialize in optimizing the currency mix, duration, and risk. They have to balance the need for liquidity with the desire to earn a return. It's a real profession, and it's become more important as reserves have grown. Luna: And what about the impact on the US? When central banks buy Treasuries, they're essentially lending to the US government. That helps keep US interest rates lower than they otherwise would be. Lucas: That's the flip side of the exorbitant privilege. Foreign central banks hold over three trillion dollars in US Treasuries, which makes up a significant portion of foreign holdings. That demand supports the Treasury market and lowers yields. But it also means the US is reliant on foreign buyers, a source of vulnerability if they ever decide to shift away. Luna: We've seen some selling in recent years. China has reduced its Treasury holdings to the lowest levels in over a decade. Is that a threat to the US? Lucas: Not yet. China's sales are more about managing its exchange rate and diversifying, not a deliberate attempt to weaponize the dollar. And they've been buying other assets like gold and European bonds. It's a slow shift, not a sudden dump. The markets can absorb it. But it's a sign that the era of automatic dollar accumulation is over. Luna: So what's the future of reserves? Will we see a multipolar currency system? Lucas: Possibly, but it's going to be a slow transition. The euro and the yuan are the main challengers, but they both have structural issues. The eurozone lacks a unified fiscal policy, and China has capital controls. So the dollar will likely remain dominant for decades. But central banks will keep diversifying at the margins, and that might be enough to shift the balance of power. Luna: And for the average person, the level of a country's reserves actually affects things like import prices and currency strength, which hits your wallet. Lucas: Absolutely. If your country's reserves are too low, you might see inflation spike when the currency depreciates. So even though it's a behind the scenes concept, it has real consequences for the cost of living. Luna: It's one of those things you never think about until you see the numbers. Trillions sitting in central bank vaults, quietly shaping the global economy. Lucas: And that's the point. It's quiet, but it's powerful. And the next time you hear about a country's foreign exchange reserves, you'll know the real story behind them.