* Futures up: Dow 50 pts; S&P 3 pts; Nasdaq 12.75 pts
July 31 (Reuters) - U.S. stock index futures were slightly higher on Monday with investors assessing Corporate America's second quarter earnings scorecard while waiting for a clutch of economic data.
* Of the 289 S&P 500 companies that reported results until Friday, 73 percent of them beat analyst expectations. This is above the 71 percent average over the past four quarters, according to Thomson Reuters I/B/E/S.
* Investors have been counting on earnings to support the relatively high valuations for equities. The S&P 500 is trading at about 18 times earnings estimates for the next 12 months, above its long-term average of 15 times.
* Apple Inc, a part of the Dow, is expected to report quarterly results after market close on Tuesday and its performance may hold the sway over tech stocks this week.
* The S&P 500 slipped on Friday on negative reactions to earnings reports from high-profile names such as Amazon , Exxon and Starbucks and a drop in shares of tobacco companies.
* Data vying for attention includes ISM Chicago Purchasing Managers' Index data that is expected at 9:45 a.m. ET. The reading, which is an indicator of the strength of U.S. manufacturing sector, is likely to show a slight dip in July.
* The Federal Reserve of Dallas will release its monthly manufacturing index for July at around 10:30 a.m. ET.
* Even as oil prices were slightly down on Monday, July was on track to become the strongest month for the commodity this year.
* Scripps Network was up 1.23 percent at $87.98 premarket after Discovery Communications said it would buy the media company for $14.6 billion.
* Dynavax Technologies was up 108 percent at $19.25 in heavy premarket trading after its experimental hepatitis B vaccine received positive feedback from a panel of expert advisers to the U.S. Food and Drug Administration.
Futures snapshot at 7:39 a.m. ET (11:39 GMT):
* S&P 500 e-minis were up 3 points, or 0.12 percent, with 123,122 contracts changing hands.
* Nasdaq 100 e-minis were up 12.75 points, or 0.22 percent, in volume of 24,251 contracts.
* Dow e-minis were up 50 points, or 0.23 percent, with 18,665 contracts changing hands. (Reporting by Sweta Singh and Yashaswini Swamynathan in Bengaluru; Editing by Arun Koyyur)