The S&P 500 is a renowned benchmark for large-cap U.S. equities and is widely referenced as the gauge of U.S. equity performance. But what is the relevance of the U.S. market and the S&P 500 internationally?

1. When we talk about the U.S. market, just how big is it?

Jodie: The S&P 500 is the proxy for the U.S. market, and it represents about 80%-85% of the U.S. stock market. But from a global perspective, the U.S. is over one-half of the global stock market, as measured by the S&P Global BMI. This really matters because as the U.S. economy grows, it propels the stock markets of all other countries—and the U.S. stock market is largely driven by consumer spending. So really, the more a country exports to the U.S., the more sensitive it becomes to U.S. growth. For example, a country like Korea has a high sensitivity and on average, rises nearly 9.5% for every 1% of U.S. growth, whereas the UK only grows about 2.5%. So you can see the differences in impact per country.