The Dow slipped on Friday and the S&P 500 was flat as falling oil prices pressured energy shares, but Microsoft boosted the Nasdaq and tech sector after positive broker comments for the software maker.

Microsoft jumped 2.6 percent to $24.11 after Goldman Sachs added shares of the world's largest software company to its Americas conviction buy list and said new products and an increase in information technology spending should underpin growth.

Energy shares led the Dow lower and dragged on the S&P 500 as oil prices fell below $70 a barrel on bets there would be ample fuel supply for the summer vacation season.

While rising oil prices can be a positive signal that demand and the global economy are strengthening, higher prices are a hindrance on consumers who are already curbing spending. Exxon Mobil fell 1.2 percent to $70.57.

Markets were also buffeted by the end of the two-day quadruple witching period, the expiration and settlement of June stock and index futures and options, which can increase volatility.

You would expect to see some intraday volatility, which may not be measured by the VIX, because most of the activity is in the June contracts which expire and settle today, said Joe Kinahan, chief derivatives strategist at online brokerage firm thinkorswim Group in Chicago.

The Dow Jones industrial average <.DJI> lost 37.63 points, or 0.44 percent, to 8,517.97. The Standard & Poor's 500 Index <.SPX> was up just 0.04 point, or unchanged on a percentage basis, at 918.41. The Nasdaq Composite Index <.IXIC> gained 13.21 points, or 0.73 percent, to 1,820.93.

Four types of June futures and options contracts expire or settle on Friday, a quarterly event that tends to generate high volume as investors adjust or exercise their derivative positions. This can heighten volatility, though the CBOE Volatility Index <.VIX> was down 5.3 percent.

Technology shares' gains helped support the S&P 500.

Apple Inc rose 1.3 percent to $137.60 as its latest iPhone hit stores. While the new product release drew crowds to Apple's flagship New York store, the line was shorter than for previous launches.

(Additional reporting by Doris Frankel; Editing by Jan Paschal)