Integrated oil majors Exxon Mobile Corporation and Chevron Corporation went head-to-head before the bell, though neither scored a knock-out.
Exxon (NYSE:XOM) shares were off 1.8% in screen-based trading, after it missed earnings expectations.
Second quarter net income of US$3.35bn was equivalent to 78 US cents, and although this was up from 41 US cents a year earlier, the market had been expecting a number around 84 US cents.
Chevron (NYSE:CVX) fared a bit better, with its shares down 0.1%, after it returned to profit in the second quarter.
Net income of US$1.5bn was equivalent to 77 US cents a share, compared to a loss of US$1.5bn or 78 US cents a share.
Revenue rose to US$33bn from US$28bn.
Drugs developer Merck & Co Inc (NYSE:MRK) edged higher in pre-market trading after second quarter sales of US$9.9bn topped the consensus forecast of US$9.75bn.
Earnings per share on the company's preferred measure clocked in at US$1.01, and the company guided the market to expect the full-year outcome to be somewhere between US$3.76 and US$3.88; that gives a midpoint of US$3.82, which is about three cents below the consensus.
The company said a cyber-attack in late June would constrain full-year performance.
The attack disrupted the company's operations worldwide and it admitted it still does not know “the magnitude of the impact of the disruption”.
American Airlines Group Inc (NASDAQ:AAL) lost altitude in pre-market trading after its second quarter earnings, even though they topped expectations.
Adjusted earnings per share of US$1.92 were five US cents ahead of expectations and up 8% year-on-year.
Revenues rose 7.2% to US$11.11bn, a shade ahead of the consensus estimate of US$11.09bn.