* S&P 500 has ended higher 13 times in the past 16 sessions
* Amazon, Zynga shares pressured in premarket after results
* Futures down: S&P 4.8 pts; Dow 38 pts; Nasdaq 8 pts
NEW YORK, July 26 (Reuters) - U.S. stock index futures fell on Friday as the market took a breather from a recent rally that has taken the S&P 500 up 18.5 percent for the year and as investors digested a slew of major earnings.
* Major U.S. stock indexes have advanced steadily this year with the S&P 500 hitting an all-time high earlier this week. The broad market index has ended higher 13 times in the past 16 sessions. For July, the benchmark index has added 5.2 percent.
* S&P 500 futures fell 4.8 points and were below fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures fell 38 points, and Nasdaq 100 futures lost 8 points.
* In earnings, Starbucks Inc shares rose 6.6 percent to $72.69 in premarket trade, a day after the world's biggest coffee chain posted a bigger-than-expected jump in quarterly profit after new fruit "Refresher" energy drinks and seasonal Frappuccino iced beverages helped drive more visits to shops in the United States, its top market.
* On the downside, Amazon.com Inc shares fell 1.9 percent to $297.52 in premarket trade one a day after the company forecast disappointing income and revenue as it grapples with a weaker international market, overshadowing improved profit and economic conditions in the United States.
* Zynga Inc shares plunged 18.6 percent in premarket trade a day after the company announced it will largely abandon its long-running efforts to build a real-money gaming business in the United States, a prospect investors once believed to be the struggling company's sole lifeline.
* Tyco International Ltd and Stanley Black & Decker are among companies that report on Friday. As of Thursday's close, 47 percent of the S&P 500 companies reported earnings, and about 68 percent of them have topped profit forecasts, above the historical average of 63 percent. About 56 percent have reported better-than-expected revenue, a rate that is below the historical average.
* European shares edged lower on Friday. Germany's DAX market had already unsettled some investors this week with profit warnings from some of its leading companies.
* In Asia, Japan's Nikkei share average slid 3 percent and was near a three-week low on Friday, with blue-chip exporters and financials leading declines on the back of a stronger yen and profit-taking.