Health insurer WellPoint Inc fell after posting lower quarterly profit as it grappled with soaring medical costs. WellPoint slipped 1 percent to $123.55.
But consumer products group Clorox Co rose 0.5 percent to $58.89 after its results topped Wall Street estimates, with quarterly profit rising more than six-fold.
The Dow Jones industrial average was up 5.85 points, or 0.05 percent, at 10,721.98. The Standard & Poor's 500 Index was down 0.64 points, or 0.05 percent, at 1,202.39. The Nasdaq Composite Index was down 2.53 points, or 0.12 percent, at 2,084.13.
Investors paused for breath following Friday's gains when the S&P closed at a high for the year and all three indexes posted their best percentage gains this year.
"Most of the earnings are out. There's not a lot of economic news out this week and there wasn't a lot of fundamental news over the weekend or this morning, so it's a pretty quiet session," said Tim Heekin, director of trading at San Francisco investment bank Thomas Weisel Partners.
US crude oil futures fell 85 cents to $45.63 a barrel after Opec producers signalled the cartel could wait until its meeting in mid-March to consider cutting production.
That helped ease concerns about corporate profit margins and consumer spending. However, energy companies slipped lower as crude fell, with Exxon Mobil Corp down 0.9 percent at $54.80.
Pharmaceuticals were strong, with Pfizer Inc up 2.3 percent at $24.79 and Merck & Co 41 cents higher, or 1.45 percent, to $28.76.
"It's a slow rotational day, with some profits being taken in energy and people bottom-fishing in some of the beaten-up pharma sectors," said Heekin.
Among other movers, payroll processing company Paychex Inc rose 2.3 percent to $30.62 after UBS Investment Research raised its investment rating to "buy" from "neutral".
Traders were also keeping watch on President George W. Bush's budget. Bush on Monday proposed a $2.5 trillion budget that slashes domestic programs from farm aid to housing grants for the poor, as he sought to curb budget deficits that have soared on his watch.