The Standard and Poor's (S&P) 500 Index is an American stock market index based on the market capitalization of 500 stocks, each one chosen for its market size, liquidity and industry. All stocks are from companies listed on the New York Stock Exchange (NYSE) or National Association of Securities Dealers Automated Quotations (NASDAQ). As of Feb. 29, 2016, the total market capitalization of all S&P 500 stocks was $17.76 trillion.

The performances of most equity managers are pegged against the S&P 500, because this index is widely considered to cover all major areas of U.S. companies. Although all S&P 500 companies are based in the United States, their revenues are generated internationally across industries. The total revenue generated by S&P 500 companies over the 12 months prior to April 2016 was $10.64 trillion.

S&P 500 Revenue by Country

More than two-thirds of revenue earned by S&P 500 companies is generated in the United States. In fact, the revenue earned by its companies in the United States had increased 2%, from 67.2% last year to 68.5%, as of March 2016. This is an indication of the strength of the dollar and weakening purchasing power of foreign currencies. The second-largest revenue-generating country is China. China produced 4.9% of total revenue in the past 12 months as of March 2016 and increased the amount of total revenue for which it was responsible by 9.2%. The country providing the third-most revenue to S&P 500 companies was the United Kingdom. Although Japan and Canada round out the top five countries, both locations have experienced a three-year decline, with shrinking revenue exposure.

S&P 500 Revenue by Region

Because of the strong foothold from the United States, 74.9% of the total S&P 500 revenue was generated in the Americas, as of March 2016. This is an increase from 73.6% in 2015. Again, this signifies the strength of the dollar. Due to the appreciation of the value of the dollar, international companies are more likely to experience greater sales with this strong currency, as opposed to a weakening one. Europe comes in second by providing 11.4% of the S&P 500 revenue. However, the Asia-Pacific region is gaining ground; it increased its revenue exposure by 0.2% to 11.3%. The African/Middle East region provides the smallest amount of support by contributing just 2.6% of revenue.

S&P 500 Revenue by Economy

As of March 2016, developed economies contributed 85.6% of the total revenue earned by S&P 500 companies, which was an increase from 84.9% last year. The emerging markets slightly declined from last year, as they only provided 11.3% of the total revenue in 2016, down from 11.5% in 2015. Frontier economies provided 1.3% of total revenue. All other markets contributed around 1.7%.

S&P 500 Revenue by Industry

The information technology sector makes up the largest sector of the S&P 500. As of March 31, 2016, information technology companies comprised 20.8% of the S&P. In 2015, over half of the sales from this sector, 59.39%, came from information technology companies outside the United States. While a large part of this is explained by outsourcing to foreign companies, this gap may widen as the United States shifts toward high-wage requirements.

Approximately 56.2% of revenue generated by energy companies came from outside the United States, although energy companies comprised less than 7% of the S&P 500. Although less than 16% of the S&P 500 is comprised of financial companies, almost 70% of the revenue earned by these financial companies is generated within the United States.

S&P 500 Revenue by Largest Companies

In 2015, Exxon Mobil Corporation (NYSE: XOM) generated 67.3% of its revenue outside the United States. It earned $115.3 billion in Canada and $39.8 billion in Europe. Intel Corporation (NASDAQ: INTC) earned $31.7 billion, or 82.4% of its revenue, in Asia. Apple Inc. (NASDAQ: AAPL) earned 62.3% of its $49.1 billion of revenue in Asia. General Electric Company (NYSE: GE) earned over half of its revenue outside the United States, including $28.7 billion in Africa, $25.3 billion in Europe and $24 billion in Asia.