Nasdaq 100 Leaders and Laggards: AMGN NVDA

The index, which includes 100 of the largest nonfinancial securities listed on the Nasdaq Stock Market, rose 0.20 points to 1,816.35. The broader Nasdaq composite fell 6.08 points to 2,245.38.

Light, sweet crude for August delivery added 28 cents to $143.85 on the Nymex. Earlier in the day, prices rose as high as $145.85 a barrel, topping a trading record set Wednesday.

Meanwhile, the Institute for Supply Management said its index of service sector activity fell to 48.2 from 51.7 in May. The Labor Department said the nation's unemployment rate held steady at 5.5 percent last month.

Shares of biotechnology company Amgen Inc. rose $2, or 4.1 percent, to $50.84.

Shares of Juniper Networks Inc., which develops networking products, gained 88 cents, or 4 percent, to $22.75.

Shares of truck maker Paccar Inc. increased 94 cents, or 2.4 percent, to $40.80.

On the falling side, shares of Nvidia Corp. plunged $5.54, or 30.7 percent, to $12.49 after the graphics chip maker lowered its second-quarter revenue outlook. Earlier in the session, shares touched a 52-week low of $12.40.

Shares of Leap Wireless International Inc. lost $4.25, or 10.5 percent, to $36.42. Rival low-cost wireless carrier MetroPCS Communications Inc. posted disappointing subscriber numbers for its second quarter Thursday.

Shares of beverage maker Hansen Natural Corp. dropped $1.88, or 6.9 percent, to $25.25.