Gianluca Benigno on the Basics and Policy Functionality of R** and the Dollar's Imperial Circle

Episode Summary

Executive Summary: Gianluca Benigno discusses three linked ideas: traditional R-star as a neutral real rate for macro stabilization, his R-double-star concept as a benchmark for financial instability in interest-rate space, and the global role of the dollar in shaping both manufacturing cycles and U.S. outcomes. He also explains his global supply chain index and how it helped trace pandemic-era inflation dynamics.

Main Topics: Career path and central banking experience (Priority: 4/5): Benigno traces his path from macro studies in Italy and Berkeley to the Bank of England, LSE, and the New York Fed, emphasizing his work during the 2007-08 financial crisis and the pandemic era. What R-star measures and why it matters (Priority: 5/5): He defines R-star as the real interest rate consistent with macroeconomic stability and explains how it is used to judge whether policy is restrictive or accommodative. Limitations of R-star estimation (Priority: 5/5): The conversation highlights that R-star is unobservable and model-dependent, requiring humility and multiple estimates because different frameworks can produce different values. R-double-star as a financial stability benchmark (Priority: 5/5): Benigno presents R-double-star as a way to translate financial stress into interest-rate space, enabling comparisons with the policy rate and scenario analysis for financial stability. Global supply chain pressure index and inflation (Priority: 4/5): He explains how the New York Fed index was built to isolate supply-side disruptions during the pandemic and why it was useful for interpreting goods and PPI inflation. The dollar’s imperial circle (Priority: 5/5): Benigno describes the dollar as a dominant macroeconomic variable that shapes the world manufacturing cycle and feeds back into the U.S. economy through an asymmetric global structure.

Key Arguments: R-star is best understood as the interest rate consistent with output-gap closure and stable inflation, and it is useful as a benchmark for monetary policy stance. Any estimate of R-star depends on a model and unobserved variables, so policymakers should use multiple perspectives and exercise humility. R-double-star extends the neutral-rate idea to financial stability by identifying the interest-rate threshold at which tightening may trigger financial stress. In the current environment, financial stability concerns may be as important as, or even more important than, macro stabilization when setting rates. The global supply chain index was designed to strip out demand effects and capture supply-side disruptions, especially during the pandemic. The dollar is not only a dominant currency but a dominant macroeconomic force that amplifies global manufacturing cycles and circles back to affect the U.S. economy. Because the U.S. is more service-oriented and less exposed to global trade than many other economies, dollar appreciation can hurt the rest of the world more than the U.S. The Fed’s domestic mandate does not eliminate its global role; swap lines and backstop facilities are necessary because dollar-centered financial stress can feed back into U.S. conditions.

Data Points: New York Fed tenure: 1 year and 1 month - Benigno says his first stint at the New York Fed lasted from August 2007 to shortly after Lehman’s collapse. First New York Fed arrival: August 2007 - He arrived just as the global financial crisis began to intensify. Pandemic/financial stress backdrop: March 2020 - The host references the pandemic-era stress episode as another period when Benigno’s work was especially relevant. R-star definition: 0 numeric value mentioned - The discussion is conceptual rather than numeric, focusing on R-star as the neutral real rate for macro stability. Global supply chain index timing: Late 2021 - Benigno says the index was developed in the midst of the pandemic, toward the end of 2021. Historical event referenced: Lehman collapse - Benigno left the New York Fed shortly after Lehman Brothers failed.

Pivotal Quotes: "the interest rate that is consistent with macroeconomic stability" — Gianluca Benigno: Benigno defines R-star at the start of the discussion. "how can we translate financial stress into a measure that is a measure that we can relate to policy instrument, which is the interest rate" — Gianluca Benigno: He explains the core idea behind R-double-star. "the dollar is not just the dominant currency, but it is a dominant macroeconomic variable" — Gianluca Benigno: He summarizes the central claim of the Dollar’s Imperial Circle paper.

Implications: Listeners should think of policy as balancing macro stability, financial stability, and global spillovers. The episode suggests central banks need broader toolkits, more humility around latent-parameter estimates, and stronger backstops for dollar-linked global stress.