Let's Talk About Exchange Rates!

Hey everyone! Ever wondered why the price of that new video game from Japan changes, or how much your money is really worth when you're planning a holiday abroad? That's all about exchange rates! It might sound complicated, but it's a huge part of our daily lives, especially in an international city like Hong Kong.

In this chapter, we're going to break down what exchange rates are, how they change, and how those changes affect prices and trade. We'll also look at Hong Kong's own special system. Don't worry if it seems tricky at first – we'll use simple examples and analogies to make it crystal clear. Let's get started!


1. The Basics: What is an Exchange Rate?

So, what's the big idea?

An exchange rate is simply the price of one country's currency in terms of another currency.

Think of it like this: You know the price of a can of coke is about HK\$7. In the world of currencies, the "price" of 1 US dollar might be HK\$7.8. That's the exchange rate!

  • Example: If the exchange rate is US\$1 = HK\$7.8, it means you need HK\$7.8 to buy US\$1.
  • It also means that 1 HK dollar can buy \(\frac{1}{7.8} \approx \text{US\$}0.128\).

How Exchange Rates Change

Currencies don't always have the same value. They can get stronger or weaker. We use different words for these changes depending on the type of exchange rate system a country has.

For Currencies that 'Float' (like the Japanese Yen or British Pound):

These currencies change value based on market forces (demand and supply). We call these changes appreciation and depreciation.

  • Appreciation: When a currency appreciates, it becomes stronger or more valuable. It can now buy MORE of a foreign currency.
    Example: If the HKD appreciates against the Japanese Yen (JPY), the rate might change from HK\$1 = JPY 20 to HK\$1 = JPY 22. Your one HK dollar now gets you more yen! Great for a trip to Tokyo!

  • Depreciation: When a currency depreciates, it becomes weaker or less valuable. It can now buy LESS of a foreign currency.
    Example: If the HKD depreciates against the JPY, the rate might change from HK\$1 = JPY 20 to HK\$1 = JPY 18. Your one HK dollar now gets you fewer yen.

Memory Aid: Think App-reciation = Value goes Up. Dep-reciation = Value goes Down (like in a depression).

For Currencies that are 'Fixed' (like the HKD used to be in certain periods):

Sometimes, a government or central bank officially sets the exchange rate. When they decide to change it, we use special terms.

  • Revaluation: An official increase in the value of a currency under a fixed exchange rate system. This is a deliberate policy decision.

  • Devaluation: An official decrease in the value of a currency under a fixed exchange rate system. This is also a deliberate policy decision.
Quick Review Box: Don't Mix Them Up!

This is a common point of confusion, so let's make it simple:

  • Appreciation / Depreciation = Caused by market forces. Happens in a floating system.
  • Revaluation / Devaluation = Caused by an official government decision. Happens in a fixed system.
Key Takeaway for Section 1

An exchange rate is the price of a currency. When a currency gets stronger, it's called appreciation (market) or revaluation (official). When it gets weaker, it's called depreciation (market) or devaluation (official).


2. How Exchange Rate Changes Affect Trade

Okay, so the value of the HKD changes. Why should we care? Because it directly affects the price of things we buy from other countries (imports) and the things we sell to other countries (exports). Let's walk through it step-by-step.

Scenario: The Hong Kong Dollar (HKD) APPRECIATES

Let's imagine the exchange rate changes from US\$1 = HK\$7.8 (the old rate) to US\$1 = HK\$7.5 (the new rate).
The HKD is now stronger because you need FEWER HKD to buy one USD.

Step 1: Effect on Import Prices

An import is something we buy from another country, like an iPhone made in the US.

  • Let's say an iPhone costs US\$1,000.
  • Price in Foreign Currency (USD): For the American seller, the price is still US\$1,000. That doesn't change.
  • Price in Domestic Currency (HKD):
    At the old rate: \(\text{US\$}1,000 \times 7.8 = \text{HK\$}7,800\)
    At the new rate: \(\text{US\$}1,000 \times 7.5 = \text{HK\$}7,500\)
  • Conclusion: The iPhone becomes cheaper for people in Hong Kong!
Step 2: Effect on Export Prices

An export is something we sell to another country, like a piece of clothing made in Hong Kong.

  • Let's say the clothing costs HK\$780.
  • Price in Domestic Currency (HKD): For the Hong Kong seller, the price is still HK\$780.
  • Price in Foreign Currency (USD):
    At the old rate: \(\frac{\text{HK\$}780}{7.8} = \text{US\$}100\)
    At the new rate: \(\frac{\text{HK\$}780}{7.5} = \text{US\$}104\)
  • Conclusion: The HK-made clothing becomes more expensive for people in the US!
Step 3: Effect on Import & Export Volume (Quantity)

This is just the Law of Demand! People buy more of things that are cheaper, and less of things that are more expensive.

  • Import Volume: Since imports are now cheaper for HK residents, the quantity demanded of imports will increase. (We'll buy more iPhones!)
  • Export Volume: Since our exports are now more expensive for foreigners, the quantity demanded of exports will decrease. (Americans will buy less of our clothing.)
Step 4: Effect on Import & Export Value (Total Spending)

Recall that \(\text{Total Value} = \text{Price} \times \text{Quantity}\).

  • Value of Imports in Foreign Currency (USD): The USD price is unchanged, but import quantity increases. Therefore, total import value in USD increases.
  • Value of Exports in Domestic Currency (HKD): The HKD price is unchanged, but export quantity decreases. Therefore, total export value in HKD decreases.
  • Total Value and Price Elasticity of Demand (\(E_d\)):
    When measuring the total value of imports in domestic currency (HKD) (where HKD price drops and quantity rises) or exports in foreign currency (USD) (where USD price rises and quantity drops), the outcome depends on the Price Elasticity of Demand (\(E_d\)):
    • If demand is elastic (\(E_d > 1\)): The percentage change in quantity is greater than the percentage change in price. For imports in HKD, total value increases; for exports in USD, total value decreases.
    • If demand is inelastic (\(E_d < 1\)): The percentage change in quantity is smaller than the percentage change in price. For imports in HKD, total value decreases; for exports in USD, total value increases.
    • If demand is unit elastic (\(E_d = 1\)): The total value remains unchanged.

Summary Table: Your Ultimate Cheat Sheet!

When our currency (HKD) APPRECIATES (gets stronger)...

Import Price (in HKD): ↓ Cheaper
Export Price (in USD): ↑ More Expensive
Import Volume (Quantity): ↑ Increases
Export Volume (Quantity): ↓ Decreases

When our currency (HKD) DEPRECIATES (gets weaker)... (e.g., US\$1 = HK\$8)

Import Price (in HKD): ↑ More Expensive
Export Price (in USD): ↓ Cheaper
Import Volume (Quantity): ↓ Decreases
Export Volume (Quantity): ↑ Increases

Key Takeaway for Section 2

A stronger home currency makes imports cheaper in domestic currency and exports more expensive in foreign currency, increasing import volume and decreasing export volume. The change in total expenditure/revenue across both currencies depends on the Price Elasticity of Demand (\(E_d\)).


3. Hong Kong's Linked Exchange Rate System (LERS)

Hong Kong has a unique system to manage its currency. Instead of letting it float freely, we "link" or "peg" it to the US dollar. Let's see how this works.

A Brief History of the HKD

The HKD wasn't always linked to the USD. It's had a few changes:

  • Before 1972: Linked to the British Pound.
  • 1972 - 1974: Switched to being linked to the US Dollar.
  • 1974 - 1983: The HKD was floated. This period had a lot of economic uncertainty, which led to a crisis of confidence.
  • October 1983 - Today: The Linked Exchange Rate System (LERS) was introduced to bring stability, linking the HKD to the USD at a rate of US\$1 = HK\$7.8.

The Note-Issuing Mechanism: The Currency Board System

The LERS is a type of currency board system. This is the foundation that makes the link so strong. Here’s the simple version of how it works:

The Rule: Commercial banknotes in Hong Kong are issued by three note-issuing banks (HSBC, Standard Chartered, and Bank of China), while HK\$10 notes and coins are issued directly by the HKSAR Government. To issue HKD banknotes, note-issuing banks MUST submit an equivalent amount of US dollars at the fixed rate of \(\text{US\$}1 = \text{HK\$}7.8\) to the Hong Kong Monetary Authority (HKMA) to obtain Certificates of Indebtedness.

Step-by-step Process:
  1. A note-issuing bank, like HSBC, wants to print HK\$78 million in new banknotes.
  2. Before doing that, it must deposit US\$10 million (since \(\frac{\text{HK\$}78\text{m}}{7.8} = \text{US\$}10\text{m}\)) into the Exchange Fund managed by the HKMA.
  3. Only after depositing the US dollars can the bank issue the new HKD banknotes.

What this means: Every single Hong Kong dollar banknote in circulation is 100% backed by US dollar reserves. This gives people and businesses enormous confidence in the value of the HKD, because they know it is fully backed by USD at the fixed rate.

An Everyday Analogy: The Arcade

Think of the HKMA as the token machine at an arcade.
- The US dollars are your real money.
- The Hong Kong dollars are the arcade tokens.
You can't just get tokens for free. You must put your real money (USD) into the machine to get tokens (HKD). The machine will only ever give out as many tokens as it has received real money to back them up. This ensures the tokens always have a stable, reliable value inside the arcade.

Did you know?

The rate of 7.8 is the official rate for issuing banknotes. In the foreign exchange market, the HKMA maintains exchange rate stability within the Convertibility Zone of 7.75 to 7.85 HKD per USD.

Key Takeaway for Section 3

Hong Kong uses a Linked Exchange Rate System, which is a currency board. This means every HKD banknote is 100% backed by US dollars held in the Exchange Fund. This system was introduced in October 1983 to provide monetary stability.