The US dollar’s historic plunge – its steepest first-half decline in five decades – may be abating. After tumbling by 10.7 percent through June, the greenback has recovered from its lows.

As of June 30, analysts projected S&P 500 earnings to grow 4.9% year over year in the second quarter, according to FactSet. That estimate was revised up to 5.6% as of July 18. Even so, if earnings ...