The S&P 500 is set for a small loss for the month, despite a deeper slide in some of the A.I. stocks that exert a heavy influence on the index.

© Jeenah Moon/Reuters

Amazon on Thursday became the latest tech company to announce swelling investments in A.I. amid stumbling share prices.

© Nathan Howard for The New York Times

The chatbot helped a woman taper off a lifesaving drug and hide the plan from her doctors.