Profit Margins and Stock Valuations

When Will Stocks Drop? Watch Profit Margins (and Get Nervous)
https://www.bloomberg.com/opinion/articles/2021-08-02/stock-market-margin-mayhem-looms-large-over-bull-market
 
Are Stratospheric Stock Valuations Here to Stay?
https://www.bloomberg.com/opinion/articles/2021-07-30/are-stratospheric-stock-valuations-here-to-stay