Barriers to Global Capital Allocation

Overview

Research Question. Why do observed international investment positions and cross-country differences in rates of return to capital fail to conform to a frictionless capital-market benchmark? The paper asks how large the efficiency and distributional costs of barriers to global capital allocation are, and which frictions — capital income taxes, political risk, and geographic/cultural/linguistic distances — matter most.

Model. The authors develop a multi-country dynamic spatial general equilibrium model in which the entire network of bilateral cross-border investment positions is endogenously determined. Production in each country i follows a three-factor Cobb-Douglas function in reproducible capital, labor, and natural resources, with country-varying income shares. Capital is the only mobile factor. A logit asset demand system governs portfolio shares: the share of country j’s savings invested in country i is proportional to the risk-adjusted expected return on capital in i, scaled by the capital stock of i, and inversely proportional to a bilateral portfolio wedge ∆ij. These wedges can be microfounded via either rational inattention (where wedges reflect the precision of prior beliefs about returns) or extreme-value-distributed transaction costs. The model admits multiple microfoundations but yields the same functional form and the same counterfactual welfare calculations regardless of interpretation.

Frictions measured. Three categories of frictions enter the empirical implementation: (a) bilateral capital income tax rates — a new dataset covering 225 countries (50,625 country pairs), constructed from corporate income tax rates and treaty-adjusted withholding tax rates on dividends and interest, further adjusted for effective tax rates accounting for tax-haven routing; (b) political risk, proxied by an ICRG composite index (excluding socioeconomic conditions) following Alfaro, Kalemli-Ozcan, and Volosovych (2008); (c) geo-political distance, comprising geographic distance, cultural distance (based on 496 World Values Survey questions across 116 countries), and linguistic distance (based on a language-family tree covering 6,737 languages and 242 countries). These distance measures are publicly available at geopoliticaldistance.org. The model covers 96 countries (9,216 dyads), representing 92% of world GDP in 2017.

Gravity Estimation. Bilateral investment data (restated for tax havens using the nationality-basis methodology of Coppola et al. 2020 and Damgaard et al. 2019) are regressed on cultural, geographic, and linguistic distance with origin and destination fixed effects. In OLS, a one-standard-deviation increase in cultural distance (0.023 units) is associated with a 24.0% decrease in foreign assets; geographic distance (0.977 units in logs) with a 78.6% decrease; linguistic distance (0.174 units) with a 51.5% decrease. These magnitudes are robust across OLS, PPML, and IV (using religious distance as an instrument for cultural distance). Under IV, the standardized effect of cultural distance on log foreign assets rises to −76.5%.

Tax haven analysis. A Tobit regression of the share of bilateral investment routed through tax havens on the estimated tax saving from routing through havens yields coefficients of 0.413–0.999 for equity and 1.001–1.777 for debt (across specifications with varying fixed effects), confirming that tax incentives are a primary driver of the discrepancy between residency-based and nationality-based bilateral positions.

Model fit (untargeted moments). The calibrated baseline model produces: (i) a correlation of 0.658 between model-implied and empirical rates of return to capital (vs. 0.325 for the frictionless benchmark), with a standard deviation of 0.417 (vs. 0.091 frictionless; data: 0.496); (ii) a correlation of 0.947 between model-implied and empirical capital per employee (vs. 0.918 frictionless); (iii) a correlation of 0.94 between model-implied and empirical home bias; the model reproduces the mean home bias of 3.973 vs. 4.006 in data and standard deviation of 1.065 vs. 1.224, while the frictionless benchmark produces exactly zero home bias for all countries. Portfolio-share MSE: 1.16 (baseline) vs. 1.86 (frictionless).

Counterfactual findings. Removing all measured barriers raises world GDP by 6.8% relative to the observed equilibrium (equivalent to stating that the distorted equilibrium is 6.8% below the frictionless benchmark). Geo-political distance alone accounts for most of this: when only distance frictions are retained, world GDP is 5.2% below the frictionless level. Capital taxes alone reduce world GDP by 2.6% below frictionless; political risk alone by 0.4%. The standard deviation of log capital per employee is 51.5% higher than it would be without barriers; the standard deviation of log output per employee is 22.5% higher. In the frictionless equilibrium, capital flows from rich to poor countries (the correlation between net foreign assets and development doubles in absolute value), accounting for the Lucas (1990) puzzle. In short-term (one-period) counterfactuals holding wealth fixed, the GDP gain from full barrier removal is 3.6%; the inequality effect remains similar (standard deviation of log capital per employee 48.4% higher with barriers).

Scope conditions. The model focuses on steady-state outcomes; dynamic transition effects are analyzed in extensions but are smaller. Quantitative conclusions are conditioned on: (i) the model sample of 96 countries covering 92% of world GDP in 2017; (ii) the conservative OLS coefficient estimates used for baseline calibration (IV estimates are larger and would amplify results); (iii) the assumption that the logit demand system captures frictions regardless of their microfoundation; (iv) omission of goods-trade frictions from the baseline (when included, the world GDP effect falls to 3.7% and the capital inequality effect to 23.3%).

Q&A

Q1. What is the core theoretical prediction about cross-country rates of return when investment barriers exist? A: In the model’s frictionless benchmark (Propositions 1 and 2), all origin countries hold identical portfolios and risk-adjusted expected returns are equalized across destinations. When bilateral frictions are introduced, countries that are more “peripheral” (harder to access for foreign investors due to high geo-political distance or political risk) receive less inward capital and therefore command higher physical rates of return to capital. Countries that are easily accessible (“central”) attract more capital and exhibit lower rates of return. The Dual Efficiency Theorem establishes that capital is efficiently allocated if and only if marginal products of capital are equalized across countries, which requires that taxes are uniform and that portfolio wedges satisfy a specific cancellation condition.

Q2. How are portfolio wedges measured, and what is the identifying strategy? A: Portfolio wedges ∆ij are decomposed into a geo-political distance component and a political risk component. The geo-political distance component is specified as a log-linear function of geographic distance, cultural distance, and linguistic distance, with coefficients (β_g, β_c, β_l) estimated from a gravity regression of log bilateral investment on these distances, controlling for origin and destination fixed effects. Because political risk varies only by destination country, it cannot be separately identified from destination fixed effects in the bilateral regression; its elasticity is therefore taken from Alfaro, Kalemli-Ozcan, and Volosovych (2008). The key identification advantage of bilateral data is that origin and destination fixed effects absorb all country-level confounders, so the distance coefficients are identified purely from within-origin, within-destination variation across country pairs.

Q3. What do the OLS gravity regressions find, and are the coefficients stable across specifications? A: In the baseline OLS specification (Table 2, column 1), the estimated coefficients on cultural distance, geographic distance, and linguistic distance are −11.944, −1.579, and −4.162 respectively (all significant at the 1% level). In standardized terms, a one-standard-deviation increase in cultural distance reduces foreign assets by 24.0%, geographic distance by 78.6%, and linguistic distance by 51.5%. Adding a rich set of control variables (colonial ties, legal origin, currency pegs, trade agreements, effective tax rates) leaves these magnitudes broadly similar: standardized effects on foreign assets are −26.4%, −80.1%, and −47.6%, respectively. Results are also robust across OLS and PPML specifications and across years 2013–2017. Effects are quantitatively similar for foreign equity and foreign debt, though linguistic distance has a somewhat smaller effect on debt.

Q4. How does the instrumental variable strategy address reverse causality in cultural distance, and what does it find? A: The authors instrument cultural distance with religious distance (based on historical trees of religious affiliation), assuming religious history affects international investment only through its contemporary effect on differences in values and beliefs as captured by the World Values Survey. The instrument is a strong predictor of cultural distance (passes weak-instrument tests comfortably). Under IV, the standardized effect of a one-standard-deviation increase in cultural distance on log foreign assets rises from −24.0% (OLS) to −76.5% (IV). The authors use conservative OLS estimates for their baseline calibration, so the IV results imply the headline counterfactual effects are likely understated.

Q5. How does the model predict home bias, and how well does it match the data? A: Home bias is defined as the log difference between the domestic portfolio share and the country’s share in the world capital stock. In the frictionless model, Proposition 1 implies that all countries hold identical foreign portfolios, so the model produces exactly zero home bias for every country. The baseline model, by incorporating bilateral frictions, generates home bias endogenously without targeting it. The model-implied home bias correlates with the empirically measured home bias at 0.94 across countries and matches both the mean (3.973 model vs. 4.006 data) and standard deviation (1.065 vs. 1.224) closely. The model also predicts, consistent with Lau, Ng, and Zhang (2010), that home bias and rates of return on capital are positively correlated (model-implied ρ = 0.55), and that rates of return on capital correlate negatively with the log of GDP per employee (model-implied ρ = −0.70).

Q6. What is the quantitative decomposition of the world GDP loss by type of barrier? A: World GDP in the observed (distorted) equilibrium is measured at $112.9 trillion (PPP), which is 6.8% below the frictionless counterfactual. When all barriers are present except geo-political distance, world GDP is 5.2% below frictionless — meaning distance frictions account for the largest share. When all barriers are present except political risk, world GDP is only 0.4% below frictionless. When all barriers are present except taxes, world GDP is 2.6% below frictionless. These are not exactly additive because the distortions interact; the results confirm that geo-political distance (cultural, linguistic, and geographic) constitutes the dominant source of global capital misallocation among the three measured frictions.

Q7. How do barriers affect the cross-country distribution of capital and income? A: The standard deviation of log capital per employee is 51.5% higher in the distorted equilibrium than in the frictionless counterfactual; the standard deviation of log output per employee is 22.5% higher. When only geo-political distance distortions are maintained, dispersion in log capital per employee is 38.2% higher and in log output per employee 15.9% higher. Maintaining only taxes raises the dispersion in log capital per employee by 12.9% and log output per employee by 6.0%; maintaining only political risk raises them by 7.3% and 3.8%, respectively. In the frictionless equilibrium, the poorest countries gain the most: some of the poorest countries see capital per employee increase by an order of magnitude and income per employee double.

Q8. Does the model account for the Lucas puzzle (capital not flowing from rich to poor countries)? A: Yes. In the observed distorted equilibrium, net foreign asset positions correlate only weakly with the level of development, consistent with Lucas’s (1990) observation that capital fails to flow from rich to poor countries. In the frictionless counterfactual, the absolute value of the correlation between net foreign asset positions and log GDP per employee doubles, and capital indeed flows from rich to poor countries as neoclassical theory predicts. The distortions from taxes, political risk, and geo-political distance thus account for the absence of a strong correlation between net positions and development in the data.

Q9. How do extensions incorporating goods-trade frictions, capital controls, and currency hedging costs affect the headline findings? A: Adding goods-trade frictions (country-specific prices for output and capital installation following Monge-Naranjo et al. 2019) reduces the world GDP effect to 3.7% (from 6.8% baseline) and the dispersion of log capital per employee to 23.3% higher (from 51.5%), but the overall pattern of results is preserved. Replacing political risk with capital controls (using Jahan and Wang 2016 de-jure capital account openness) yields a comparable world GDP loss of 6.6% and a geo-political distance effect of 6.2%, very close to the 6.8% and 5.2% in the baseline. Adding currency hedging costs leaves world GDP loss and inequality effects essentially unchanged relative to baseline. None of these extensions materially alters the headline conclusions.

Q10. How do the authors validate the model against nationality-based versus residency-based bilateral investment data? A: The model is calibrated to nationality-based positions (restated for tax havens). The MSE for fitting nationality-based external portfolio shares is 1.16, while the MSE for residency-based positions is 1.22. The model was not explicitly designed to distinguish between the two, yet it naturally produces better predictions for nationality-based positions because its frictions incorporate the incentives for indirect investment routing through tax havens. This cross-validation supports the methodological approach of using nationality-restated data and confirms the internal consistency of the model’s treatment of tax-haven routing.

Q11. What are the implications for global tax policy coordination? A: In the presence of information frictions, simple harmonization of capital tax rates across countries does not improve capital allocation efficiency and could worsen it. The Dual Efficiency Theorem implies that efficient capital allocation in a world with information frictions requires that taxes, risk premia, and information frictions satisfy a joint cancellation condition. From a normative perspective, a global social planner maximizing world GDP should impose lower capital tax rates in countries that are “peripheral” in the network of informational distances, in order to offset the disadvantage created by information frictions for those countries.

Q12. How is the elasticity parameter η calibrated, and how sensitive are the results? A: The elasticity of substitution among countries’ assets, η, is calibrated at 18.5 based on Koijen and Yogo (2020)’s demand-price elasticities for long-term debt (3.1, converted to a gross-return elasticity of approximately 30), short-term debt (25.2, converted to approximately 24.3), and equity (1.3, converted to approximately 14.8), with weights reflecting the composition of global portfolios. The baseline gravity coefficients are calibrated from OLS with controls (cultural: −13.129, geographic: −1.645, linguistic: −3.850), chosen as conservative estimates relative to IV or PPML. Sensitivity analysis using PPML or IV estimates of β yields broadly similar steady-state GDP losses (around 6%), confirming robustness.

Key Concepts

Portfolio wedge (∆ij): A bilateral distortionary term in the logit asset demand system that captures all frictions reducing the ability of investors from country j to invest in country i. Decomposed empirically into a geo-political distance component and a political risk component. A wedge of 1 means no friction; larger values reduce the share of investment flowing from j to i. Can be interpreted either as prior-belief imprecision under rational inattention or as systematic transaction costs under the extreme-value microfoundation.

Geo-political distance: A composite of geographic distance (population-weighted geodesic distance), cultural distance (expected disagreement in World Values Survey responses between randomly drawn individuals from two countries, constructed with the “flex” method using up to 496 questions), and linguistic distance (normalized tree distance in the Ethnologue language family graph, covering 6,737 languages). Distinct from simple physical distance: it captures the informational and transactional barriers that arise from societal dissimilarity.

Dual Efficiency Theorem: A theoretical result (Theorem in Section 2.8) establishing that capital efficient allocation, equalization of marginal products of capital across countries, and uniform taxes combined with a specific cancellation condition on portfolio wedges are mutually equivalent statements in steady-state equilibrium. This is not a restatement of the First Welfare Theorem; it is a statement about GDP (not welfare) and does not require risk premia to be equalized.

Effective bilateral tax rate (τij): The composite bilateral tax rate on capital after accounting for tax-haven routing. Firms in the destination country optimally choose the share of capital issued through tax havens (solving a quadratic cost optimization), trading off the lower tax rate available through havens against an increasing quadratic routing cost. The effective rate is therefore lower than the statutory (de jure) rate when the tax-haven rate is lower than the statutory rate, with the gap depending on the estimated βth coefficient from the Tobit regressions.

Logit asset demand system: A portfolio allocation rule in which the share of country j’s savings invested in destination country i is proportional to the risk-adjusted expected return raised to the power η (the elasticity of substitution) times the destination capital stock, divided by the portfolio wedge and summed over all destinations. Microfounded either by rational inattention (Matejka and McKay 2015; Pellegrino 2023) or by extreme-value-distributed transaction costs. Produces portfolio gravity analogous to trade gravity when combined with the market clearing conditions.

Home bias: Defined as the log difference between a country’s domestic portfolio share (πii, the share of domestic savings invested at home) and that country’s share of world capital stock (ki/K). In the frictionless benchmark, home bias is exactly zero for all countries by Proposition 1. The baseline model generates home bias endogenously as a consequence of portfolio wedges and reproduces both the level and cross-sectional distribution of empirically observed home bias without targeting these moments directly.

Core-periphery structure: An emergent property of international capital markets under investment barriers: countries that are easily accessible to international investors (low geo-political distance, low political risk, favorable tax treatment) are “central” and attract capital inflows, driving their rates of return to capital lower; “peripheral” countries that are less accessible have smaller capital stocks and higher rates of return, compensating investors for overcoming barriers. This structure generates persistent capital misallocation and cross-country income inequality.

Nationality-based vs. residency-based bilateral investment positions: Residency-based data (e.g., raw IMF CPIS) attributes investment to the immediate counterparty country, including tax-haven shell companies. Nationality-based data (Coppola et al. 2020; Damgaard et al. 2019; Beck et al. 2024) reattributes investment to the country of the ultimate investor and ultimate issuer, bypassing offshore centers. The model fits nationality-based positions better (MSE 1.16 vs. 1.22 for residency-based) because it incorporates frictions that generate incentives for indirect routing, which is what nationality restatement is designed to undo.