HEALTHCARE DEAL: Johnson & Johnson accepted an offer of about $4 billion from the private equity firm Carlyle Group to buy its Ortho-Clinical Diagnostics business. J&J said the deal for the blood-testing unit should close by mid-year. J&J rose 70 cents, or 0.8 percent, to $98.15.
QUARTER END: Trading is expected to be heavier and more volatile Monday as investors close out their first-quarter positions. At the end of each quarter, fund managers will often sell their worst-performing stocks and buy more of their best-performing stocks in an effort to make their portfolios look better when investors get their quarterly statements. The phenomenon has the Wall Street nickname of "window dressing." If the stock market closes higher Monday, it would be the fifth-straight quarterly rise for the S&P 500.
"There's a lot of re-allocation going on today," said J.J. Kinahan, chief strategist with TD Ameritrade.
YELLEN: In a speech, Federal Reserve Chair Janet Yellen said Monday that she thinks the struggling U.S. job market will continue to need the help of low interest rates "for some time." Her remarks come after investors have grown anxious that the Fed might raise short-term rates starting in mid-2015. Yellen has previously suggested that the Fed could start raising short-term rates six months after it halts its bond purchases, which most economists expect by year's end.
SIGNS OF LIFE: After getting hammered for days, biotechnology stocks were rising again. Gilead was up 3 percent, Vertex Pharmaceuticals rose 4 percent and Biogen Idec rose 3.5 percent. Investors had been pulling money out of biotech stocks for the last month and refocused on less volatile areas of the market such as utilities and health care. The S&P 500 Biotechnology Index is down 10 percent his month, even with Monday's gains.