U.S. stocks traded slightly higher Thursday, with the Nasdaq composite and S&P 500 index receiving a boost after shares of e-commerce company Amazon.com Inc. leaped around 3 percent. The S&P 500 hit a new intraday high of 2,133.20. 

In afternoon trading, the Dow (INDEXDJX:.DJI) added more than 10 points, or 0.06 percent, to reach 18,312. The Standard & Poor's 500 (INDEXNASDAQ:.IXIC) rose 5.65 points, or 0.27 percent, to 2,132.94. The Nasdaq composite (INDEXSP:.INX) gained 22.84 points, or 0.45 percent, to reach 5,094.

Shares of Amazon.com Inc. (NASDAQ:AMZN) jumped nearly 3 percent Thursday after the e-commerce giant announced its Amazon Prime Now service is offering one-hour delivery from local stores in Manhattan, including groceries, meals and baked goods, through the Amazon Prime Now app. Amazon’s stock gained 2.9 percent to as high as $436.48 in morning trading.

Meanwhile, Lumber Liquidators Holdings Inc. (NYSE:LL), the largest U.S. retailer of hardwood flooring, saw its shares plunge 17 percent Thursday after CEO Robert Lynch unexpectedly resigned. The news comes less than a month after the company’s chief financial officer, Daniel Terrell, stepped down, the company said.

CVS Health Corp. (NYSE:CVS) announced Thursday it plans to buy healthcare services company Omnicare Inc. (NYSE:OCR) for $12.7 billion in a deal to expand the second-largest U.S. drugstore operator’s presence in the growing senior healthcare market. In morning trading, CVS Health and Omnicare gained 3 percent and 1.7 percent, respectively.

Shares of Best Buy Co. Inc. (NYSE:BBY) jumped 6 percent Thursday to as high as $36.60 after the consumer electronics retailer's profit and revenue beat Wall Street forecasts last quarter, boosted by sales of large-screen televisions, mobile phones and appliances.

Caterpillar Inc. (NYSE:CAT), the world’s largest manufacturer of construction and mining equipment, was the biggest gainer in the Dow Thursday, up 1.7 percent, while McDonald's Corporation (NYSE:MCD) was the largest decliner, shedding 0.7 percent.

The number of Americans filing new claims for unemployment rose slightly more than expected last week as initial claims for state unemployment benefits increased 10,000 to a seasonally adjusted 274,000 for the week ended May 16, the U.S. Labor Department said Thursday.

Economists had forecast jobless claims to rise 7,000 to 271,000 last week, according to analysts polled by Thomson Reuters.

Separately, U.S. existing home sales unexpectedly fell in April, dropping 3.3 percent to an annual rate of 5.04 million units, the National Association of Realtors said Thursday. 

Notable companies reporting earnings after the closing bell Thursday include Hewlett-Packard Company, the world’s second-biggest PC manufacturer.