In the build up to the Second World War, the United States was the major power with the highest gross domestic product (GDP) per capita in the world. In 1938, the United States also had the highest overall GDP in the world, and by a significant margin, however differences in GDP per person were much smaller. Switzerland In terms of countries that played a notable economic role in the war, the neutral country of Switzerland had the highest GDP per capita in the world. A large part of this was due to the strength of Switzerland's financial system. Most major currencies abandoned the gold standard early in the Great Depression, however the Swiss Franc remained tied to it until late 1936. This meant that it was the most stable, freely convertible currency available as the world recovered from the Depression, and other major powers of the time sold large amounts of gold to Swiss banks in order to trade internationally. Switzerland was eventually surrounded on all sides by Axis territories and lived under the constant threat of invasion in the war's early years, however Swiss strategic military planning and economic leverage made an invasion potentially more expensive than it was worth. Switzerland maintained its neutrality throughout the war, trading with both sides, although its financial involvement in the Holocaust remains a point of controversy. Why look at GDP per capita? While overall GDP is a stronger indicator of a state's ability to fund its war effort, GDP per capita is more useful in giving context to a country's economic power in relation to its size and providing an insight into living standards and wealth distribution across societies. For example, Germany and the USSR had fairly similar GDPs in 1938, whereas Germany's per capita GDP was more than double that of the Soviet Union. Germany was much more industrialized and technologically advanced than the USSR, and its citizens generally had a greater quality of life. However these factors did not guarantee victory - the fact that the Soviet Union could better withstand the war of attrition and call upon its larger population to replenish its forces greatly contributed to its eventual victory over Germany in 1945.

Between the Wall Street Crash of 1929 and the end of the Great Depression in the late 1930s, the Soviet Union saw the largest growth in its gross domestic product, growing by more than 70 percent between 1929 and 1937/8. The Great Depression began in 1929 in the United States, following the stock market crash in late October. The inter-connectedness of the global economy, particularly between North America and Europe, then came to the fore as the collapse of the U.S. economy exposed the instabilities of other industrialized countries. In contrast, the economic isolation of the Soviet Union and its detachment from the capitalist system meant that it was relatively shielded from these events. 1929-1932 The Soviet Union was one of just three countries listed that experienced GDP growth during the first three years of the Great Depression, with Bulgaria and Denmark being the other two. Bulgaria experienced the largest GDP growth over these three years, increasing by 27 percent, although it was also the only country to experience a decline in growth over the second period. The majority of other European countries saw their GDP growth fall in the depression's early years. However, none experienced the same level of decline as the United States, which dropped by 28 percent. 1932-1938 In the remaining years before the Second World War, all of the listed countries saw their GDP grow significantly, particularly Germany, the Soviet Union, and the United States. Coincidentally, these were the three most powerful nations during the Second World War. This recovery was primarily driven by industrialization, and, again, the U.S., USSR, and Germany all experienced the highest level of industrial growth between 1932 and 1938.

On October 29, 1929, the U.S. experienced the most devastating stock market crash in it's history. The Wall Street Crash of 1929 set in motion the Great Depression, which lasted for twelve years and affected virtually all industrialized countries. In the United States, GDP fell to it's lowest recorded level of just 57 billion U.S dollars in 1933, before rising again shortly before the Second World War. After the war, GDP fluctuated, but it increased gradually until the Great Recession in 2008. Real GDP Real GDP allows us to compare GDP over time, by adjusting all figures for inflation. In this case, all numbers have been adjusted to the value of the US dollar in FY2012. While GDP rose every year between 1946 and 2008, when this is adjusted for inflation it can see that the real GDP dropped at least once in every decade except the 1960s and 2010s. The Great Recession Apart from the Great Depression, and immediately after WWII, there have been two times where both GDP and real GDP dropped together. The first was during the Great Recession, which lasted from December 2007 until June 2009 in the US, although its impact was felt for years after this. After the collapse of the financial sector in the US, the government famously bailed out some of the country's largest banking and lending institutions. Since recovery began in late 2009, US GDP has grown year-on-year, and reached 21.4 trillion dollars in 2019. The coronavirus pandemic and the associated lockdowns then saw GDP fall again, for the first time in a decade. As economic recovery from the pandemic has been compounded by supply chain issues, inflation, and rising global geopolitical instability, it remains to be seen what the future holds for the U.S. economy.

The Covid-19 pandemic saw growth fall by 2.2 percent, compared with an increase of 2.5 percent the year before. The last time the real GDP growth rates fell by a similar level was during the Great Recession in 2009, and the only other time since the Second World War where real GDP fell by more than one percent was in the early 1980s recession. The given records began following the Wall Street Crash in 1929, and GDP growth fluctuated greatly between the Great Depression and the 1950s, before growth became more consistent.

During the 19th century, the United States generally had a negative trade balance, importing more than it exported, particularly from the British Empire. This changed at the turn of the 20th century, and the U.S. consistently had a positive trade balance between 1896 and 1970. The greatest periods of fluctuation came during the world wars, as well as an observable decline following the Wall Street Crash of 1929.

While inflation rates increased the total value of imports and exports over time, the rate of growth did increase significantly from 1900 onwards. The early 20th century saw the U.S. move away from its traditional isolationist policies (apart from a brief period during the great Depression) and emerge as a global superpower. Following the Second World War, the U.S. used its economic power to maintain its influence across the globe, as it sought to suppress the expansion of communism.

The Standard & Poor’s (S&P) 500 Index is an index of 500 leading publicly traded companies in the United States. In 2021, the index value closed at 4,766.18 points, which was the second highest value on record despite the economic effects of the global coronavirus (COVID-19) pandemic. In 2023, the index values closed at 4,769.83, the highest value ever recorded. What is the S&P 500? The S&P 500 was established in 1860 and expanded to its present form of 500 stocks in 1957. It tracks the price of stocks on the major stock exchanges in the United States, distilling their performance down to a single number that investors can use as a snapshot of the economy’s performance at a given moment. This snapshot can be explored further. For example, the index can be examined by industry sector, which gives a more detailed illustration of the economy. Other measures Being a stock market index, the S&P 500 only measures equities performance. In addition to other stock market indices, analysts will look to other indicators such as GDP growth, unemployment rates, and projected inflation. Similarly, since these indicators say something about the economic future, stock market investors will use these indicators to speculate on the stocks in the S&P 500.