The U.S.'s historic economic expansion has so enriched one-percenters they now hold almost as much wealth as the middle- and upper-middle classes combined. The top 1% of American households have enjoyed huge returns in the stock market in the past decade, to the point that they now control more than half of the equity in U.S. public and private companies, according to data from the Federal Reserve. The very richest had assets of about $35.4 trillion in the second quarter, or just shy of the $36.9 trillion held by the tens of millions of people who make up ... much of the middle and upper-middle classes. It may not be long before one-percenters actually surpass the middle and upper-middle classes. Household wealth in the upper-most bracket grew by $650 billion in the second quarter of 2019, while Americans in the 50th to 90th percentiles saw a $210 billion gain. By another measurement the top 1% of taxpayers had incomes starting at $515,371 in 2017, according to the latest Internal Revenue Service data. For now, those Americans in 90th to 99th percentiles - well-to-do, but not the super rich - still control the biggest share of wealth, with $42.6 trillion in assets. The lone group left out of the fun: the bottom 50% of Americans. Those households have 35.7% of liabilities in the U.S. and just 6.1% of assets.