NEW YORK CITY (AFP) - United States stocks on Thursday opened little changed following disappointing earnings outlooks from Dow members Cisco and Wal-Mart.

Five minutes into trade, the Dow Jones Industrial Average advanced 3.41 points (0.02 per cent) to 15,825.04.

The broad-based S&P 500 nudged 1.35 (0.08 per cent) higher to 1,783.35, while the tech-rich Nasdaq Composite Index lost 6.89 (0.17 per cent) at 3,958.69.

Cisco plummeted more than 12 per cent after company officials warned of slowing investment in China and other key emerging economies.

Wal-Mart Stores posted earnings that exceeded expectations by a penny at US$1.14 a share, but revenues lagged forecasts and the company trimmed its full-year profit forecast. Shares were off about 0.5 per cent.

Market watchers are also eyeing Capitol Hill, where Federal Reserve vice-chairman Janet Yellen testifies in her confirmation hearing for the central bank's top spot.

Ms Yellen's prepared testimony suggested she would maintain the Fed's aggressive monetary stimulus.