Which of the following is NOT a valid property of a benchmark?

A benchmark serves as a standard against which the performance of a portfolio can be measured.

The property of being unambiguous means that the benchmark's composition and structure are clearly defined and can be understood without confusion. This is essential because investors and managers need to interpret benchmark results accurately. An unambiguous benchmark allows for straightforward comparisons and meaningful performance evaluations.

Investability refers to the ability to actually replicate the benchmark through available investment vehicles. This is critical for practical application, as a benchmark should ideally be something that an investor can invest in or create a proxy for without significant barriers or costs.

Being reflective of current investment opinions means that the benchmark should align with prevailing market views and trends, representing what investors believe is an appropriate mix or segment of the market. This relevance can help ensure that the benchmark remains applicable over time.

Volatility, however, is not a desirable property of a benchmark. While some volatility is inevitable in financial markets, an effective benchmark is expected to provide a stable point of reference. If a benchmark is characterized by excessive volatility, it can lead to misleading assessments of a portfolio's performance relative to that benchmark. Therefore, this characteristic detracts from the benchmark's effectiveness in measuring consistent investment performance.