While we don’t know how much total stock market leverage there is, we can look at margin debt as a measure of the trend. And the trend has reached whopper proportions. History shows that a big surge in margin balances preceded – and perhaps was a precondition for – the biggest stock market declines:
In a chart like this that covers over two decades, the long-term increases in the absolute dollar amounts are not critical since the purchasing power of the dollar with regards to stocks has dropped. What is critical are the steep increases in margin debt before the selloffs.
https://wolfstreet.com/2021/04/17/stock-market-leverage-in-la-la-land-rises-to-historic-wtf-highs/