U.S. stock index futures fell on Thursday as renewed worries over sovereign debt in some euro zone countries kept investors away from riskier investments, including equities, ahead of U.S. jobs and factory data.

* European stocks followed Asian markets lower on concerns that Greece's fiscal problems would spread to other highly indebted euro zone countries. For details see

* Ahead of the key non-farm payrolls data Friday, the Labor Department will release weekly first-time claims for jobless benefits at 8:30 a.m. EST. Economists in a Reuters survey forecast a total of 460,000 new filings, compared with 470,000 in the prior week.

* S&P 500 futures dropped 7.2 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 fell 53 points, and Nasdaq 100 futures lost 9.5 points.

* Also at 8:30 a.m., preliminary fourth-quarter productivity data will be released.

* The Commerce Department will report December factory orders at 10 a.m. Economists expect a rise of 0.5 percent, compared with a 0.6 percent rise in the prior month.

* ICSC chain store sales for January are also due. In the previous month, sales rose 2.8 percent from the year before.

* Shares of Cisco Systems Inc rose 3 percent in light premarket trading after quarterly profit and revenues rose, easily exceeding expectations. For details, see

* Shares of Visa Inc rose as much as 2.8 percent in extended trade Wednesday after the credit card company reported

stronger-than-expected earnings.

* Rival MasterCard Inc is due to report results Thursday.

* Health insurer Cigna Corp posted a better-than-expected quarterly profit early Thursday, citing strong performance in its accident insurance business and effective operational cost controls.

* U.S. stocks mostly fell on Wednesday as Pfizer Inc's
disappointing outlook weighed on the health sector, and U.S. President Barack Obama's pledge to complete banking and healthcare reforms revived fears of increased regulation.

(Editing by Jeffrey Benkoe)