Understand currency pair trading

What Is a Currency Pair?

The Anatomy: BASE/QUOTE

Let's derive what the price means from first principles:

EUR/USD = 1.2000

What does this number mean?

• You need 1.2000 USD to buy 1 EUR
• If you have1 EUR, you can exchange it for 1.2000 USD

WHY this format? Because we're expressing the base currency (EUR) in terms of the quote currency (USD). The number tells you: "How many units of the quote currency does1 unit of the base currency cost?"

Derivation from scratch:

1. Start with the definition: $P = \frac{\text{Quote units}}{\text{Base units}}$
2. Multiply both sides by Base units: $P \times \text{Base units} = \text{Quote units}$
3. Therefore: If you trade $B$ units of base currency, you exchange $B \times P$ units of quote currency

WHY does this matter? This formula determines your profit/loss. If you buy EUR/USD at 1.2000 and sell at 1.2100, you made 0.0100 USD per EUR traded.

Major vs Cross vs Exotic Pairs

WHY categorize? Liquidity and spread costs differ dramatically. Major pairs have tight spreads (1-2 pips), exotics can be 20-50 pips.

Direct vs Indirect Quotes

HOW to remember: If your home currency is the quote (second), it's direct. If your home currency is the base (first), it's indirect.

Indirect (USD is base):

• USD/JPY = 110.00 → "My $1 gets me ¥110"
• USD/CHF = 0.9200 → "My $1 gets me 0.92 CHF"

WHY this matters for trading:

• In direct quotes: Price↑ means foreign currency strengthening vs USD
• In indirect quotes: Price ↑ means USD strengthening vs foreign currency

Bid, Ask, and Spread

Derivation of spread cost:

Suppose EUR/USD quotes: Bid 1.2000 / Ask 1.2002

If you:

1. Buy 1 EUR at Ask = 1.2002 USD spent
2. Immediately sell 1 EUR at Bid = 1.2000 USD received
3. Loss = 1.2002 - 1.2000 = 0.002 USD = 2 pips

WHY does spread exist? Market makers profit from the difference. They buy from sellers at the bid and sell to buyers at the ask, pocketing the spread.

HOW spread affects you: You must overcome the spread to break even. Tighter spreads = lower cost of trading.

Why this step? We multiply the per-unit spread (0.0003) by position size (10,000) to get dollar cost.

For a 1-pip spread: Cost would be $1 per10,000 units (this is why pip value matters!).

Cross Pair Pricing (The Triangle Trade)

Then: $\text{EUR/GBP} = \frac{A}{B}$

Derivation from first principles:

1. What we know:

   • 1 EUR = $A$ USD (from EUR/USD)
   • 1 GBP = $B$ USD (from GBP/USD)

2. What we want: How many GBP does 1 EUR cost?

3. Method: Use USD as the bridge currency:

   • 1 EUR → $A$ USD (convert EUR to USD)
   • $A$ USD → $\frac{A}{B}$ GBP (convert USD to GBP using the fact that $B$ USD = 1 GBP)

4. Therefore: $\text{EUR/GBP} = \frac{A}{B}$

WHY this works: We're chaining exchange rates. The USD cancels out mathematically.

Find EUR/GBP: $\text{EUR/GBP} = \frac{1.2000}{1.4000} = 0.8571$

Interpretation: 1 EUR = 0.8571 GBP (EUR is weaker than GBP)

Verification by logic:

• 1 EUR = 1.20 USD
• 1 GBP = 1.40 USD
• GBP is "more valuable" in USD terms
• So 1 EUR should buy less than 1 GBP ✓
• Specifically: 1 EUR buys 1.20/1.40 = 0.857 GBP ✓

Why does arbitrage keep this true? If EUR/GBP quotes differently from the calculated cross rate, traders would:

1. Buy the underpriced pair
2. Sell the overpriced pair
3. Pocket risk-free profit
4. This trading pressure forces prices back in line

Pips and Pip Value

WHY this specific convention? Historical artifact from when forex moved in percentage points. For most currencies, 0.0001 represents a ~0.01% move (100 pips = 1% at parity).

Wait—this formula looks complex. Let's derive it:

Scenario: You trade 10,000 EUR/USD at 1.2000

Step-by-step derivation:

1. What is a pip move worth in base currency?

   • Pip size for EUR/USD = 0.001
   • Position = 10,000 EUR
   • A 1-pip move changes the pair value by 0.0001

2. How much quote currency does this represent?

   • Change in quote = Position × Pip size
   • Change in quote = 10,000 × 0.0001 = 1 USD

WHY is this simpler for most pairs? When quote currency is USD (EUR/USD, GBP/USD), 1 pip on a 10,000 unit position = $1. Clean!

But for indirect quotes (USD/JPY):

If USD/JPY = 110.00, you trade 10,000 USD:

• 1 pip = 0.01 JPY
• Change = 10,000 × 0.01 = 100 JPY
• Pip value in USD = 100 / 110.00 = $0.909

Why divide by exchange rate? We need to convert the JPY profit back to USD (our account currency).

2. USD/JPY = 110.00, Position = 100,000 USD

• Pip size = 0.01
• Change = 100,000 × 0.01 = 1,000 JPY
• Pip value = 1,000 / 110.00 = $9.09 per pip

3. EUR/GBP = 0.8500, Position = 100,000 EUR

• Pip size = 0.0001
• Change = 100,000 × 0.0001 = 10 GBP
• If GBP/USD = 1.4000: Pip value = 10 × 1.4000 = $14 per pip

Why the third example needs GBP/USD? To convert GBP profit to USD account currency!

How Pairs Actually Move: Correlation

Correlation types:

• Positive correlation: EUR/USD and GBP/USD move together (both quote USD, react to USD strength/weakness)
• Negative correlation: EUR/USD and USD/CHF move opposite (USD on different sides)

WHY this matters: If you're long EUR/USD and long GBP/USD, you're really just "long anti-USD" twice—not diversified!

Mistake 1: "EUR/USD went up, so the dollar strengthened"

Why this feels right: Price going up = good, dollar is mentioned, must mean dollar is good!

The fix: In EUR/USD, EUR is base, USD is quote. Price up means EUR strengthened (more USD needed per EUR). USD weakened.

Steel-man the mistake: The confusion comes from USD being in the name. Remember: BASE wins when price rises, quote wins when price falls.

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Mistake 2: "I'll just trade exotic pairs for bigger moves"

Why this feels right: Bigger volatility = bigger profit potential!

The fix: Yes, more volatility, but also:

• Much wider spreads (could be 50pips vs 1 pip)
• Lower liquidity (harder to exit at desired price)
• More susceptible to manipulation and sudden gaps

Real calculation:

• EUR/USD: 50 pip move, 1 pip spread = 49 pips net
• USD/TRY: 100 pip move, 30 spread = 70 pips net
• Seems better, BUT: Risk of 500-pip overnight gap on Turkish central bank announcement!

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Mistake 3: "Pip value is always $10per lot"

Why this feels right: Many brokers advertise "$10 per pip per standard lot" for simplicity.

The fix: This is only true for pairs where USD is the quote currency (EUR/USD, GBP/USD). For USD/JPY, GBP/JPY, EUR/GBP, pip values differ and change as exchange rates move!

HOW to avoid: Always calculate pip value for your specific pair at current price, or check your broker's position calculator.

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Mistake 4: "I can't lose more than my position in forex"

Why this feels right: In stocks, the maximum loss is 100% (stock goes to zero).

The fix: Forex is leveraged and involves two currencies. If EUR/CHF suddenly moves 30% (happened in 2015when Swiss National Bank removed peg), and you're leveraged 50:1, you can lose far more than your initial margin.

Steel-man: The confusion comes from thinking of forex like buying a stock. In reality, you're borrowing one currency to buy another, amplifying gains AND losses.

Recall Explain Currency Pairs to a 12-Year-Old

Imagine you're at a video game trading post. You have 100 Gold Coins, and your friend has 150 Silver Coins. You want to know: "How much Silver can I get for my Gold?"

The trader says: "Gold/Silver is 1.5." This means 1 Gold Coin = 1.5 Silver Coins. So your100 Gold = 150 Silver.

Now, why would the price change? Maybe everyone suddenly wants Gold because a rumor spreads that Gold unlocks a secret level. Now the trader says "Gold/Silver is 2.0"—Gold got stronger! Your 100 Gold now = 200 Silver!

That's currency trading: betting whether Gold will get stronger or weaker against Silver. You're always comparing two things, never just "buying Gold."

The spread: The trader is sneaky. If you want to BUY Gold, he charges you 2.0 Silver per Gold. But if you want to SELL Gold, he only gives you 1.98 Silver per Gold. He keeps the 0.02 difference. That's his profit—the spread!

Why pairs always move together in groups: If Gold gets strong, it usually gets strong against BOTH Silver AND Bronze. So if you buy Gold/Silver and/Bronze, you're really just betting on Gold twice!

"Ask = Acquire" → The ask is where you ask to acquire (buy) the base currency.

For direct vs indirect: "Direct = Dollar Denominated" → If your home currency (USD for Americans) is the quote (second position), it's direct—directly in your dollars!

Connections

• 4.2.01-Stock-basics - Similar to stock pricing, but forex has no "underlying company"
• 4.2.04-Understand-derivatives - Currency futures and options are derivatives on forex pairs
• 4.3.02-Technical-analysis-basics - Chart patterns work on currency pairs, but fundamentals differ
• 4.4.01-Risk-management - Leverage in forex requires strict position sizing
• 5.1.03-Market-liquidity - Forex is the most liquid market globally ($7T daily volume)
• 4.2.07-Understand-commodities - Commodity currencies (AUD, CAD, NZD) correlate with commodity prices

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#flashcards/stock-market

What are the three components of a currency pair quote? :: Base currency (first), quote currency (second), and the exchange rate (price)

If EUR/USD = 1.2000, what does this price mean? :: 1 EUR costs 1.2000 USD, or you receive 1.2000 USD when selling 1 EUR

What is pip value for10,000 EUR/USD? :: $1 per pip (for most USD-quoted pairs: position size × 0.0001)

Concept Map

Hinglish (regional understanding)

Intuition Hinglish mein samjho

Currency pair trading ka matlab hai ki ap kabhi bhi sirf ek currency nahi khareedte ya bechte—hamesha do currencies ka exchange hota hai. Jaise agar ap EUR/USD trade kar rahe ho, toh actually aap yeh bet laga rahe ho ki "EUR, USD ke against strong hoga ya weak." Yeh ek seesaw jaisa hai—ek side upar jati hai toh dosri neeche.

Har pair mein do parts hote hain: base currency (pehli wali) aur quote currency (dosri wali). Price bata hai ki 1 unit base currency ke liye kitne quote currency chahiye. EUR/USD = 1.2000 ka matlab hai1 EUR ke liye apko 1.20 dollarsene padenge. Jab price badhta hai EUR/USD mein, iska matlab EUR strong ho raha hai (dollar weak ho raha hai), kyunki ab 1 EUR ke liye zyada dollars chahiye.

Bid aur ask prices bhi samajhna zaroori hai. Bid woh price hai jahan aap base currency bech sakte ho, aur ask woh price hai jahan aap khareed sakte ho. In dono ka difference "spread" kehlata hai—yeh market maker ka profit hai aur aapki transaction cost bhi. Har pip move (chhoti price change, usually 0.0001) ka value apke position size pe depend karta hai. Standard lot (100,000 units) mein EUR/USD ka 1 pip = $10, lekin USD/JPY jaisi indirect pairs mein pip value alag hota hai kyunki conversion chahiye.

Cross pairs (jahan USD nahi hai) ko samajhne ke l