An investment strategy or portfolio is considered market-neutral if it seeks to avoid some form of market risk entirely, typically by hedging. To evaluate market neutrality requires specifying the risk to avoid. For example, convertible arbitrage attempts to fully hedge fluctuations in the price of the underlying common stock. A portfolio is truly market-neutral if it exhibits zero correlation with the unwanted source of risk.[1] Market neutrality is an ideal, which is seldom possible in practice.[2] A portfolio that appears market-neutral may exhibit unexpected correlations as market conditions change. The risk of this occurring is called basis risk.