Exchange Rates and Asset Prices in a Global Demand System
What this paper finds — and why it matters
The paper develops an asset demand system to analyze, jointly and across all countries, how international portfolio holdings and flows, exchange rates, short-term rates, long-term yields, and equity prices are determined in equilibrium. The authors specify a nested logit model of asset demand (substitution across countries within an asset class, and across asset classes) and introduce a new instrumental-variables identification strategy based on the size distribution of countries and bilateral distances; estimating on portfolio-holdings data for 37 countries and three asset classes from 2003 to 2020, they find demand is relatively inelastic, with mean demand elasticities of 27.9 (s.e. 1.9) for short-term debt, 3.2 (0.4) for long-term debt, and 1.2 (1.1) for equity. A variance decomposition attributes 82% of exchange-rate variation, 86% of short-term-rate variation, and 60% of log market-to-book equity variation to ’latent demand’ (the residual demand shifter), while portfolio flows (54%) and macro variables (43%) dominate long-term yields. Applying the framework to the European sovereign debt crisis, latent demand explains essentially all of the Italian long-term-yield variation and 74% of the Portuguese, whereas macro fundamentals are relatively more important for Greece (46% vs. 32% for latent demand), which the authors read as consistent with Greece being insolvent while Italy and Portugal were solvent but perceived as vulnerable. Estimating the convenience yield on US assets, they find, in units of expected annual returns, 1.41% on the US dollar, 2.71% on US long-term debt, and 0.50% on US equity. All estimates are specific to their sample, model, and identification assumptions.
Summary of a forthcoming paper, AI-assisted and human-reviewed. See the linked original for the authoritative claims and full conditions.
Q1. What is a ‘global demand system’ and what does it explain?
The authors represent the equilibrium of an international macro model as an asset demand system and replace traditional optimal portfolios with estimated asset demand functions that match observed international portfolio holdings, so that portfolio flows and shifts in asset demand explain all movements in exchange rates and asset prices. This lets them reinterpret the exchange rate disconnect (Meese and Rogoff 1983) as the finding that shifts in asset demand through macro variables explain much less variation than portfolio flows and latent demand, and to identify which countries’ latent demand matters for exchange rates and asset prices.
Q2. What is the nested logit model of asset demand?
Asset demand follows a nested logit model with substitution across countries in the inner nest and across asset classes in the outer nest, where demand depends on expected returns (asset prices or yields and real exchange rates), macro variables (GDP, GDP per capita, inflation, equity volatility, sovereign rating), bilateral distance (the gravity effect), a domestic-ownership indicator (home bias), and latent demand. The nested structure gives more flexible substitution than the logit model of Koijen and Yogo (2019), while latent demand captures heterogeneous beliefs about risk exposure across investors and assets.
Q3. How are the demand elasticities identified?
The authors develop an instrumental-variables strategy in which an exogenous component of one investor group’s demand shifters generates variation in residual supply that identifies another group’s demand elasticity, isolating cross-sectional variation in residual supply from the size distribution of countries and the bilateral distances between them. Intuitively, smaller issuer countries in close proximity to larger investor countries have lower residual supply and thus higher asset prices and/or real exchange rates (the example contrasts Dutch with Australian long-term debt).
Q4. What are the estimated demand elasticities, and why do they matter?
Averaged across years and issuer countries, the mean demand elasticities are 27.9 (s.e. 1.9) for short-term debt, 3.2 (0.4) for long-term debt, and 1.2 (1.1) for equity — so, e.g., a country’s aggregate equity demand falls about 1.2% per 1% rise in its price. The authors present these as empirical targets for international macro models that rely on inelastic demand and demand shocks unrelated to fundamentals to resolve long-standing puzzles, and they note the estimates are broadly consistent with prior, more granular estimates for narrower sets of countries and asset classes once differences in aggregation and identification are accounted for.
Q5. What does the variance decomposition reveal?
Latent demand is relatively more important for exchange rates, short-term rates, and equity prices — explaining 82% of exchange-rate variation (of which foreign-exchange reserves explain 10%), 86% of short-term-rate variation, and 60% of log market-to-book equity variation — whereas portfolio flows (54%) and macro variables (43%) are relatively more important for long-term yields (latent demand explains only about 3%). For equity, North American investors explain 13% and European investors 26% of the log market-to-book variation.
Q6. How does the framework interpret the European sovereign debt crisis?
Applied to extreme long-term-yield movements in Greece, Italy, and Portugal, the decomposition shows macro variables are relatively more important for Greece (46% vs. 32% for latent demand), while latent demand explains all of the Italian and 74% of the Portuguese yield variation, with European investors alone explaining 98% of the Italian and 65% of the Portuguese movements. The authors read this as consistent with the narrative that Greece was insolvent while Italy and Portugal were solvent but perceived as vulnerable.
Q7. What are the estimated convenience yields on US assets?
Computing counterfactual prices that remove the special demand for US assets, the authors estimate convenience yields, in units of expected annual returns, of 1.41% on the US dollar, 2.71% on US long-term debt, and 0.50% on US equity. In the absence of special status, a value-weighted US-dollar exchange rate would be 5.23% higher, the US long-term yield 0.73% higher, and US market-to-book equity 3.35% lower, consistent with the view that the dollar is the global reserve currency and US Treasury debt the global safe asset.
Q8. How does the framework connect to monetary policy?
The authors note in their conclusion that, because unconventional monetary policy fundamentally concerns changes in the supply of long-term debt and its impact on exchange rates and asset prices through substitution effects, the demand-system approach is suited to study the simultaneous and cumulative impact of conventional and unconventional monetary policy across many countries — and they flag this as a direction for future research rather than a result of the current paper. This scope condition matters: the present paper estimates the demand system and its decompositions, not the effects of monetary policy itself.
Key concepts
asset demand system / demand system asset pricing : an approach (introduced in Koijen and Yogo 2019 and here extended to international finance) that estimates asset demand functions on portfolio holdings data and analyzes the equilibrium relation between holdings/flows and prices, in place of traditional optimal portfolios.
nested logit asset demand : the specific functional form for demand, with substitution across countries in the inner nest and across asset classes in the outer nest, allowing flexible substitution patterns.
latent demand : the residual component of demand shifters — capturing heterogeneous beliefs about risk exposure — that, together with portfolio flows and macro variables, accounts for movements in exchange rates and asset prices; it is the dominant driver of exchange rates and short-term rates in the decomposition.
demand elasticity (inelastic markets) : the percentage change in a country’s aggregate asset demand per 1% change in its price; the paper’s low estimates (especially 1.2 for equity) are offered as empirical targets for ‘inelastic markets’ macro-finance models.
convenience yield : the extra demand for (and hence lower expected return on) US assets owing to their special status as global reserve currency and safe asset; measured here as 1.41% (USD), 2.71% (US long-term debt), and 0.50% (US equity) in expected-annual-return units.
gravity effect and home bias : the empirical regularities that portfolio holdings decline with bilateral distance (gravity) and are tilted toward domestic assets (home bias), which the demand system captures via distance and a domestic-ownership indicator.