Which of the following metrics provides insight into global stock market sizes?

The metric that provides insight into global stock market sizes is STAT. This metric offers a comprehensive view of various financial and market statistics, including total market capitalization of stock exchanges around the world. It allows for an analysis of market sizes in relation to different regions and sectors, enabling investors and analysts to gauge the overall health and scale of global equity markets.

In contrast, other options may pertain to different aspects of financial analysis. For instance, RVR focuses on relative value, HDS might relate to historical data sets, and OWN could concern ownership structures or shareholder information. These metrics have their specific applications, but STAT is uniquely designed to provide a broad perspective on market sizes, making it the most relevant choice in this context.