Dow Drops 600 Points
Plus: Boeing shares slide 7.6% after its finance chief warned of significant cash-flow problems. Average mortgage rates fall below 7% for the first time in more than a month. J.R. Whalen reports.\n\n\n\nSign up for the WSJ's free What's News newsletter.\xa0\n\nLearn more about your ad choices. Visit megaphone.fm/adchoices