Stocks pulled back last week with the S&P 500 shedding 1.3% to close at 4,457.49. The index is now up 16.1% year to date, up 24.6% from its October 12 closing low of 3,577.03, and down 7.1% from its January 3, 2022 record closing high of 4,796.56. Recent market gains can be attributed to the outlook for earnings growth. And some of that expected earnings growth can be attributed to what’s arguably the most unexpected development in the corporate world over the past two years: The resilience of profit margins. As inflation rates surged in 2021, analysts were convinced rising...