Arbitrage, in the context of security trading, refers to the exploitation of security mispricing with the aim of making risk-free profits. This is achieved by simultaneously buying and selling the same security in different markets to take advantage of the price difference. The key element of arbitrage is that it involves no risk. The profit is made from the price discrepancy and not from the movement of the security's price. Therefore, it is considered a risk-free profit. The arbitrager, or the person conducting the arbitrage, is essentially providing a service to the market by ensuring that prices across different markets are in line with each other. If there is a price discrepancy, the arbitrager will step in to take advantage of the situation, thereby bringing the prices back into alignment. This is why arbitrage is considered an important mechanism in maintaining market efficiency.

Choice A is incorrect. While the exploitation of undervalued assets can lead to increased returns, this does not necessarily constitute arbitrage. Arbitrage specifically involves taking advantage of price discrepancies in different markets for the same asset to make risk-free profits, not simply investing in undervalued assets.

Choice C is incorrect. Timing returns accurately to obtain optimal profit from a security refers more to trading strategies based on market timing and prediction rather than arbitrage. Arbitrage does not rely on timing or predicting market movements but rather exploits existing price discrepancies between markets.

Choice D is incorrect. The exploitation of illegal trading channels for tax-free profits falls under illicit activities and has nothing to do with the concept of arbitrage in security trading which is a legal and commonly used strategy.

Things to Remember

• Arbitrage involves exploiting price discrepancies in different markets for the same asset to make risk-free profits.
• It is achieved by simultaneously buying and selling the same security in different markets to take advantage of the price difference.