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Feldstein-Horioka Puzzle

The anomaly that national saving and investment rates are strongly correlated across countries when frictionless capital mobility predicts near-zero — turning the regression slope into a continuous gauge of de facto capital-market integration.

Core Idea

The Feldstein-Horioka puzzle is an anomaly in international macroeconomics: the cross-country correlation between national saving rates and investment rates is strikingly high (about 0.89 in the original 1980 OECD panel) when frictionless capital mobility predicts it should be near zero. If markets were integrated, saving would flow to the highest global return rather than staying home. The persistently steep slope forces the conclusion that integration is far more frictional than textbook arbitrage assumes, and converts a fuzzy question into a tractable diagnostic coefficient.

Scope of Application

As a constructed diagnostic statistic it applies wherever its precondition holds: national saving and investment rates across a panel of open economies, read against the near-zero benchmark.

  • Capital-mobility measurement — the slope as a continuous indicator of de facto integration.
  • De jure vs de facto analysis — metering the gap between paper openness and actual responsiveness.
  • Eurozone-integration studies — tracking the coefficient before, during, and after the debt crisis.
  • Open-economy DSGE calibration — ruling out frictionless models and disciplining friction calibration.
  • Current-account sustainability — the within-border tethering bounding external imbalances.

Clarity

Naming the puzzle converts an almost unfalsifiable question — how integrated are global capital markets? — into a single tractable statistic the field can measure and argue over. That is its main clarifying act. Its second is sharpening the distinction between de jure and de facto mobility: a country can be open on paper while its investment stays tethered to its saving. It also disciplines theory, filtering out frictionless-arbitrage models that predict a flat relationship.

Manages Complexity

Capital-market integration is otherwise a sprawling, ill-posed object of regulations, flow data, and anecdote with no agreed verdict. The puzzle collapses it to one scalar the analyst can track, with fixed endpoints on [0,1], so "is integration advancing?" becomes the slope of that number through time. It also works as a theory filter, converting "what explains capital flows?" into the bounded "which frictions reproduce a coefficient this large?"

Abstract Reasoning

It licenses diagnostic measurement of a hidden quantity (integration) from a surface statistic; metering of the de-jure/de-facto gap; theory-filtering by one decisive prediction that rules out frictionless-arbitrage models in a stroke; predictive tracking of integration trends through the coefficient's movement; and a boundary-drawing move bounding sustainable external imbalances off the same correlation.

Knowledge Transfer

Being a diagnostic statistic wrapped in an anomaly, its transfer is governed by an instrument's precondition, not mechanism-versus-metaphor. It travels literally across international macro — country samples, decades, eurozone studies, DSGE calibration — and reasons alongside sibling puzzles like home bias. Beyond international financial flows the reach is essentially nil; the portable insight, that apparent integration can hide frictions, belongs to the primes frictions, market_integration, and arbitrage_finance.

Relationships to Other Abstractions

Local relationship map for Feldstein-Horioka PuzzleParents appear above the current abstraction, mutual partners to the right, and children below. Node labels state whether each abstraction is prime or domain-specific; colors identify relation types.Feldstein-HoriokaPuzzleDOMAINPrime abstraction: Calibration Anomaly — is a decomposition ofCalibrationAnomalyPRIMEPrime abstraction: Correlation — is a decomposition ofCorrelationPRIMEPrime abstraction: Frictionless Benchmark Reasoning — is a decomposition ofFrictionless Be…PRIME

Current abstraction Feldstein-Horioka Puzzle Domain-specific

Parents (3) — more general patterns this builds on

  • Feldstein-Horioka Puzzle is a decomposition of Calibration Anomaly Prime

    A model predicts a saving-investment slope near zero, observation produces a persistent slope near one, and the magnitude of that gap excludes the frictionless model class while constraining the missing-friction search.

  • Feldstein-Horioka Puzzle is a decomposition of Correlation Prime

    The observable payload is systematic saving-investment covariation whose regression slope supports prediction but does not identify a causal financing relation or which hidden friction generated it.

  • Feldstein-Horioka Puzzle is a decomposition of Frictionless Benchmark Reasoning Prime

    The puzzle begins from a frictionless-capital benchmark with a sharp near-zero saving-investment slope, then treats the observed residual coupling as a coordinate for cataloguing and measuring omitted frictions.

Hierarchy paths (3) — routes to 3 parentless roots

Neighborhood in Abstraction Space

Feldstein-Horioka Puzzle sits in a crowded region of the domain-specific corpus (32nd percentile for distinctiveness): several abstractions share nearly its structure, so a description that fits it tends to fit its neighbors too.

Family — Macroeconomic Puzzles & Long-Run Relations (5 abstractions)

Nearest neighbors

Computed from structural-signature embeddings · 2026-07-12