NEW YORK (AP) — Stocks are rising on Wall Street as the market comes off its biggest monthly gain in four years. Health care stocks were among the early winners as drugmakers Pfizer and AbbVie climbed.

KEEPING SCORE: The Dow Jones industrial average rose 78 points, or 0.4 percent, to 17,741 as of 11:17 a.m. Eastern time. The Standard & Poor's 500 index was up 12 points, or 0.6 percent, to 2,091. The Nasdaq composite index increased 42 points, or 0.8 percent, to 5,095.

PULL OUT THE PLASTIC: Payments processor Visa said it will buy sister company Visa Europe in a deal that could be worth more than $23 billion. Visa Europe has been a separate company since 2004. Visa dipped $2.17, or 2.8 percent, to $75.41.

REBOOTING: Hewlett-Packard officially split into two companies over the weekend and the stocks went in opposite directions. HP Inc., which will sell personal computers and printers, rose $1.47, or 12 percent, to $13.71. Hewlett Packard Enterprises will sell commercial computer systems, software and tech services. Its stock fell 59 cents, or 4 percent, to $14.17.

SLIMMING DOWN: ConAgra Foods said it will sell its private label business to TreeHouse Foods for $2.7 billion. The company will focus on name brands like Chef Boyardee and Slim Jim. Shares added 71 cents, or almost 2 percent, to $41.26.

OUTBREAK: Chipotle stumbled as an E. coli outbreak linked to restaurants in Oregon and Washington state spread. The Mexican restaurant chain has shut down all 43 of its restaurants in those states. Officials said Friday that more than 20 people have gotten sick and that number is expected to increase as word of the outbreak spreads. No deaths have been reported. Chipotle Mexican Grill lost $15.71, or 2.5 percent, to $624.52.

SHIRE EXPANDS: Irish drugmaker Shire will buy Dyax for at least $5.9 billion, or $37.30 per share. Dyax is studying treatments for a rare genetic disease called hereditary angioedema, which can cause dangerous swelling of the throat or larynx. Shire makes two other treatments for that condition. Dyax shares surged $8.44, or 30.7 percent, to $35.97.

HEALTH CARE: Drug giant Pfizer rose $1.09, or 3.2 percent, to $34.91, the biggest gain in the Dow. The shares slumped late last week on word Pfizer is in talks to buy competitor Allergan. AbbVie, which surged 10 percent Friday on strong third-quarter results, climbed $3.25, or 5.5 percent, to $62.81 after Morgan Stanley upgraded the stock.

OVERSEAS: Britain's FTSE 100 was little changed, Germany's DAX was up 0.8 percent and France's CAC 40 edged up 0.4 percent.

ENERGY: U.S. crude oil fell 44 cents, or 0.9 percent, to $46.16 a barrel on the New York Mercantile Exchange. Brent crude, which is used to price international oils, slid 44 cents, or 0.9 percent, to $49.12 a barrel in London.

BONDS, CURRENCIES: U.S government bond prices fell. The yield on the 10-year Treasury note rose to 2.18 percent from 2.15 percent Friday. The dollar edged up to 120.75 yen from 120.70 yen and the euro rose to $1.1029 from $1.0003.