Explanation

Riskless arbitrage involves simultaneously buying and selling identical or equivalent assets in different markets to profit from price discrepancies without taking any risk. The key requirements for riskless arbitrage include:

1. Liquidity (Option A): The underlying security must be relatively liquid to ensure that arbitrage positions can be established and unwound quickly without significant transaction costs or price impact.

2. Ability to sell short (Option B): Short selling is often necessary in arbitrage strategies to sell the overpriced asset while buying the underpriced equivalent. Without short selling capability, arbitrage opportunities may not be fully exploitable.

3. Being a financial asset (Option C): This is NOT a requirement for riskless arbitrage. Arbitrage opportunities can exist with:

   • Physical commodities (gold, oil, agricultural products)
   • Real assets (real estate, infrastructure)
   • Any asset that has equivalent substitutes in different markets

Key Insight: Riskless arbitrage focuses on price discrepancies between identical or equivalent assets, regardless of whether they are financial assets, physical commodities, or other types of assets. The essential requirements are the ability to establish offsetting positions (often requiring short selling) and sufficient liquidity to execute trades efficiently.

Correct Answer: C - "is a financial asset" is least likely to be a requirement because arbitrage opportunities can exist with non-financial assets as well.