The market capitalization of the US equity market has doubled over the last 4 years.
Over the same time period, the value of all other stock markets has increased by ~$10 trillion or a mere 19%.
Furthermore, over the last 10 years, US markets have added $40 trillion in value, doubling the return seen in all other markets combined.
As a result, the US now reflects a record 74% of the MSCI World Index, even surpassing the 1970s high.