No one knows what the total leverage in the stock market is. But we know it’s huge and has surged in past years, based on the limited data we have, and from reports by various brokers about their “securities-based loans” (SBLs), and from individual fiascos when, for example, a $1.6 billion SBL to just one guy blows up. There are many ways to use leverage to fund stock holdings, including credit card loans, HELOCs, loans at the institutional level, loans by companies to its executives to buy the company’s shares, or the super-hot category of SBLs, where brokers lend to their clients. None of them are reported on an overall basis.
https://wolfstreet.com/2018/11/21/stock-market-margin-debt-plunges-most-since-lehman-moment/
