* Labor market, service sector data could set payroll tone
* Crude oil jumps above $100 per barrel on unrest in Egypt
* S&P 500 struggling to break through 50-day moving average
* Futures down: Dow 103 pts, S&P 500 8.2, Nasdaq 17.25
By Ryan Vlastelica
NEW YORK, July 3 (Reuters) - U.S. stock index futures fell Wednesday ahead of an abbreviated trading session, tracking international weakness amid investor concerns about the pace of global economic growth.
* Trading could be light, with many market participants out of the office for the Fourth of July holiday in the U.S., where markets will close early on Wednesday and reopen on Friday. The limited volume could increase market volatility.
* Traders were looking to the release of a flurry of economic data, which could give some insight into the strength of Friday's closely watched payroll report.
* If the data is weak, it could have an outsized impact on financial companies, which are closely tied to the pace of economic growth. Bank of America fell 0.9 percent to $12.79 in premarket trading.
* S&P 500 futures fell 8.2 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 lost 103 points and Nasdaq 100 futures fell 17.25 points.
* The S&P 500 is 3.3 percent below its May 21 record closing high of 1,669.16, but has been unable to close above its 50-day moving average of 1,623.94 since June 20.
* The ADP national employment report will be released at 8:15 a.m. EDT (1215 GMT) and is expected to show 160,000 private sector jobs added in June, an increase of 25,000 from the previous month. Weekly jobless claims, due at 8:30 a.m. (1230 GMT), are seen dropping by 1,000 to 345,000 in the latest week.
* The Institute for Supply Management's June read on the services sector will also be closely scrutinized. The report is seen coming in at 54, compared with 53.7 in the previous month.
* Economic data has been an outsized market mover in recent weeks as investors attempt to gauge when the U.S. Federal Reserve will begin pulling in its bond-buying stimulus program, which has been credited with fueling the market's gains this year. Bullish data has led to market declines as traders worry a strong economy will mean a faster end to the policy.
* In the upcoming nonfarm payroll report, analysts expect 165,000 jobs to have been added in June, below the 175,000 added in May.
* In China, shares fell 0.6 percent after the latest economic data pointed to slowing momentum, which could have a negative impact on demand for commodities. The data pressured shares in Europe, which dropped 1.2 percent.
* Crude oil prices rose 1.4 percent to $100.99 a barrel, a 14-month high, on concerns that political unrest in Egypt could destabilize the Middle East and lead to supply disruptions.
* In corporate news, Michael Dell has been advised to raise his $24.4 billion offer for Dell Inc, coming under further pressure as billionaire investor Carl Icahn revealed he had committed more than $3 billion to back an alternative proposal.
* Avon Products Inc sold its Silpada Designs jewelry business for $85 million, three years after buying it for $650 million.