Talking Interest Rates with Ricardo Caballero

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I’m spending a lot of time thinking about high interest rates, both for obvious reasons and because I’m reconsidering some of my own long-held views. So I thought I’d have a long talk with someone who has really studied these issues and now, I believe, may have been more right than I was. This may be even wonkier than usual, but trust me, it’s important.

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TRANSCRIPT: Paul Krugman in Conversation with Ricardo Caballero

(recorded 8/25/26)

Paul Krugman: I’m talking today with a very, very serious economist, Ricardo Caballero, who is one of the most important macroeconomic thinkers of modern times. I was going to say of my generation, but actually, I’m an older generation—but of the currently, still vital creative generation. We’ve had discussions about a lot of events over the past 25 years that have involved some disputes that I hope we can get into in a way that people understand. And recent events, including the rise in long-term interest rates, have really brought all of those issues to the fore. So I thought I’d talk with Ricardo, who is the Ford International Professor of Economics at MIT, a position I once held. But anyway, hi.

Ricardo Caballero: Hi, Paul. So wonderful to see you again. We still miss you at MIT.

Krugman: Well, I miss the days when actually getting at the truth was what mattered, as opposed to dealing with all of the obvious lies. But anyway, I guess there are different stages in one’s life. But so, I will want to get into recent events. But one thing that really struck me is that there’s this long-running discussion basically around interest rates and international movements of capital where there are kind of, as I see it, two rival ways of thinking about it. It could be some of both—but one was about returns to capital and investment opportunities, and one was about people looking for safety and security in assets. And for the most part, I was on one side of that and you were on the other. And I’m starting to think that you were probably right. So, first off, how would you portray this discussion? And maybe we can go back and forth.

Caballero: I don’t know whether they’re really different views because, you know, my view at least was always, when I say “a shortage of a store-of-value,” if you will, investment opportunities create those store-of-value opportunities and so on. So I never saw it as very contradictory. I thought there was an imbalance: lots of needs for savings, in particular in a very specific kind of saving—safe saving. And the productive structure wasn’t able to generate enough assets, especially safe assets. And that’s, I think, what led to the sort of “shortage of safe assets” type of literature, and that naturally depresses safe interest rates. If you look at the return on capital, actually, it was fairly stable. It was all absorbed by the opportunity risk premium, if you will. And so you can see returns both on safe and risky capital sort of declining in tandem since 2000, or earlier than that. And then somewhere around 2000, you can see that the safe interest rate keeps coming down, while the return to capital is sort of paralyzed. And what starts widening is the equity risk premium.

Krugman: So let me just break in here. A kind of crude, simplistic view—probably my view at a certain point—was that there’s capital and then there are returns on capital. And when we start to see interest rates get really low circa 2000, that’s telling you that returns to capital are going down. And if we see a lot of money coming to the United States, it’s because, well, America had faster population growth than other rich countries, and we were leading the technology revolution. But you’re saying there’s a really big difference between buying stock—corporate investment—and buying U.S. government debt, which is safe. And that the United States was sort of better than the rest of the world at supplying these safe assets.

Caballero: Absolutely.

K