US stocks open lower ahead of Yellen speech

New York - US stocks Friday opened modestly lower ahead of a major speech by Federal Reserve chair Janet Yellen that could shed light on the central bank's plans for monetary policy.

Five minutes into trade, the Dow Jones Industrial Average fell 25.49 points (0.15%) to 17 014.00.

The broad-based S&P 500 retreated slightly from Thursday's record, dipping 2.88 (0.14%) to 1 989.49, while the tech-rich Nasdaq Composite Index slid 2.97 (0.07%) to 4 529.13.

Yellen is scheduled to address an annual central banker gathering in Jackson Hole, Wyoming at 16:00. The topic of her speech is the labour market, but investors will be looking for hints on whether the Fed could speed up its timetable for raising benchmark interest rates.