Currency quotes, real exchange rates and capital flows

Learning goals

• Name the currency units before calculating a change in value.
• Compare exchange-rate regimes, flow channels and objectives of capital restrictions.

Draft · approximately 45 minutes, excluding further revision.

One currency’s price is another currency’s unit

Write S as domestic currency per one foreign currency. A rise in S means the foreign currency buys more domestic currency, so the domestic currency depreciates in this quotation. Its reciprocal is foreign per domestic; percentage changes are not equal and opposite because the denominator changes. Name the base and price currency rather than relying on an ambiguous slash convention.

A real exchange-rate index under this definition is q=S×Pforeign/Pdomestic with a consistent base. A rise is a real depreciation of the domestic currency: foreign goods become more expensive relative to domestic goods in common-currency terms. Price indices measure relative changes, not an exact universal fair-value exchange rate; baskets, tradability and productivity differ.

Regimes and flows change the adjustment mechanism

FX participants include businesses settling trade, investors, banks and other intermediaries, central banks and speculators. Spot exchange settles a near-term currency transaction; forwards fix a future exchange under a contract. Hedging an exposure differs from taking a new speculative exposure, even when both use the same instrument. Trade invoices, debt denomination and asset ownership determine who gains or loses from a currency move.

A hard peg, managed arrangement and floating regime place different roles on reserves, policy rates and market prices. Depreciation may improve an exporter’s receipts but raise imported-input and foreign-debt costs; volume adjustment can lag. Capital controls may aim to limit destabilizing flows, preserve policy room or manage external funding pressure, while potentially reducing access, efficiency or confidence. The applicable law, instruments and effectiveness need current evidence; this lesson makes no country-specific claim.

Formula and assumptions

Foreign appreciation = S₁/S₀−1; domestic value change = S₀/S₁−1; real FX index q = S×Pforeign/Pdomestic

Asymmetric currency percentage changes

1. S rises from 25 to 26 domestic units per foreign unit. The foreign currency appreciates 26/25−1=4% in domestic terms.
2. Domestic currency value in foreign units changes by 25/26−1=−3.8462%, not −4%.
3. If domestic prices rise 5% and foreign prices 2%, the real index ratio is 1.04×1.02/1.05=1.010286: domestic real depreciation about 1.0286% under the stated convention.

Errors to catch

• Reversing the currency units in the middle of a percentage calculation.
• Assuming depreciation benefits every domestic company.

Original knowledge check

Answer every question before checking. Review explanations after submitting; retry starts a new attempt.

Sources and coverage status

These original lessons are drafts. Public outlines are used to check scope; the official learning-outcome text and proprietary question banks are not reproduced here. Follow the source for exam-year requirements and updates.

• Reference · www.cfainstitute.org