Arbitrage

A financial strategy involving the simultaneous purchase and sale of an asset in different markets to profit from price differences.
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In one sentence

Arbitrage is earning a low-risk profit by buying an asset where it is cheap and (nearly) simultaneously selling where it is expensive, pushing prices toward equality (the “law of one price”).

How it works (basic mechanics)

If the same asset trades at two different prices after accounting for fees and frictions, an arbitrageur can:

  • buy at the lower price,
  • sell at the higher price,
  • lock in the spread (minus costs).

Why it matters

Arbitrage is one of the forces that:

  • links prices across markets and exchanges,
  • keeps derivatives and spot prices aligned,
  • helps enforce “no-arbitrage” pricing in finance (e.g., covered interest parity, option pricing).

Common types

  • Spatial arbitrage: same asset, different venues/locations.
  • Triangular FX arbitrage: inconsistencies across three exchange rates.
  • Statistical arbitrage: relative-value trades that rely on models (usually not risk-free).

Real-world frictions (why “risk-free” is not guaranteed)

  • transaction costs and bid-ask spreads,
  • execution latency and price moves,
  • funding/borrow constraints (shorting),
  • settlement risk and operational risk,
  • capital and regulatory limits.

Flow of an arbitrage trade

    flowchart TD
	  A["Observe two prices"] --> B{"Spread > costs?"}
	  B -- No --> C["No trade"]
	  B -- Yes --> D["Buy low venue"]
	  D --> E["Sell high venue"]
	  E --> F["Hedge/settle/close legs"]
	  F --> G["Spread captured<br/>(net of costs)"]
  1. No Arbitrage: A fundamental principle asserting that exploitable arbitrage opportunities should not exist if markets are efficient.
  2. Market Efficiency: The degree to which market prices reflect all available, relevant information.
  3. Interest Arbitrage: A strategy involving borrowing in a market with lower interest rates while lending in a market with higher ones to profit from the interest rate differential.

Quiz

### Which of the following describes arbitrage? - [x] Buying an asset in one market and selling it in another market simultaneously to exploit price differences. - [ ] Holding an asset and waiting for long-term capital appreciation. - [ ] Combining various securities to form a diversified portfolio. - [ ] Engaging in highly speculative, high-risk trades to earn profits. > **Explanation:** Arbitrage specifically involves the simultaneous purchase and sale of an asset in different markets to exploit price discrepancies for profit. ### What usually limits the profits made from arbitrage? - [ ] Time of day - [ ] Exchange rates - [x] Transaction costs - [ ] Market sentiment > **Explanation:** Transaction costs can substantially limit the profit margins available in arbitrage activities. ### True or False: Arbitrage is always completely risk-free. - [ ] True - [x] False > **Explanation:** Although arbitrage aims to be risk-free, minor risks can arise from execution lags or market volatility. ### The process of borrowing in a market with lower interest rates and lending in a market with higher interest rates is known as: - [ ] Speculation - [ ] Hedging - [x] Interest arbitrage - [ ] Currency trading > **Explanation:** Interest arbitrage involves borrowing at lower interest rates and lending at higher interest rates to profit from the difference. ### Which term is closely related to arbitrage prevention? - [x] No-Arbitrage Condition - [ ] Market Indifference - [ ] Zero-Sum Game - [ ] Risk Premium > **Explanation:** The No-Arbitrage Condition suggests that equivalent assets should trade at the same price, preventing arbitrage opportunities. ### Which activity involves accepting high risk for high potential gains, unlike arbitrage? - [ ] Diversification - [ ] Hedging - [ ] Capital Budgeting - [x] Speculation > **Explanation:** Speculation involves high-risk transactions with substantial gain potential, differing fundamentally from the risk-averse strategy of arbitrage. ### Etymologically, the word "arbitrage" comes from which languages? - [x] French - [ ] German - [ ] Latin - [ ] Italian > **Explanation:** The term *arbitrage* is derived from the French word *arbitrer*, which means to judge or arbitrate. ### In financial markets, arbitrage helps to make markets more... - [x] Efficient - [ ] Volatile - [ ] Speculative - [ ] Unpredictable > **Explanation:** Arbitrage opportunities tend to close gaps in prices across different markets, promoting market efficiency. ### Which regulatory body oversees and ensures fair trading practices that could involve arbitrage activities in the U.S.? - [ ] World Bank - [ ] European Central Bank - [ ] International Monetary Fund (IMF) - [x] U.S. Securities and Exchange Commission (SEC) > **Explanation:** The SEC plays a pivotal role in regulating and overseeing financial markets in the United States. ### What typically happens to arbitrage opportunities once they are identified and acted upon? - [ ] They last for several days - [ ] They become more profitable - [ ] They disappear immediately - [x] They usually close quickly > **Explanation:** Arbitrage opportunities often dissipate rapidly once traders exploit them, as market prices adjust to close gaps.
Arbitrage Pricing Theory
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