Equities have fallen much of August due to the latest escalations in the trade conflict between Washington and Beijing and as Treasury bond yields have gyrated with investors anxious about slowing global growth.

US stocks rallied on Thursday from recent lows, but were under pressure again early Friday.

About 15 minutes into trading, the Dow Jones Industrial Average stood at 26,322.87, down 0.2 percent.

The broad-based S&P 500 shed 0.3 percent to 2,929.04, while the tech-rich Nasdaq Composite Index fell 0.5 percent to 7,998.79.

Uber plunged 8.8 percent after it reported a bigger-than-expected $5.2 billion loss in the second quarter, exacerbating worries about the ride-hailing company's long-term path to profitability.

Mattel tumbled 11.2 percent after the toy company abruptly canceled a debt offering to raise $250 million, saying it received "an anonymous whistleblower letter" that it needed to investigate.