* Key employment data on tap
* Aetna profit misses Street view
* Cost to insure Greek, Portuguese, Spanish debt rises
* Futures: Dow down 46 pts; S&P down 5.5; Nasdaq up 0.25
* For up-to-the-minute market news, click [STXNEWS/US]
NEW YORK, Feb 5 (Reuters) - U.S. stock index futures fell on Friday, following Wall Street's worst day in more than nine months, as lingering worries over the fiscal health of some European countries curbed risk appetite ahead of a key U.S. jobs report.
* S&P 500 futures SPc1 fell 5.5 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 DJc1 lost 46 points, and Nasdaq 100 futures NDc1 up 0.25 points.
* A Reuters poll predicted non-farm payrolls grew by 5,000 in January, after an unexpected loss of 85,000 in December. The unemployment rate is expected to edge up to 10.1 percent in January from 10 percent. The government jobs report is due at 8:30 a.m. EST (1330 GMT).
* The cost of insuring Greek, Portuguese and Spanish government debt rose to record highs Friday on mounting fears about debt defaults. Many investors had their eyes on Portugal, where parliament was to vote on a regional financing bill seen as a crucial test of the government's ability to curb public spending. For details see [ID:nEUROPEAND].
* Aetna Inc (AET.N) posted lower quarterly profit early Friday, missing the average estimate, on high medical costs for its commercial health plans. The big health insurer also forecast 2010 profit below Wall Street's target. [ID:nN05139992]
* Shares of Illumina Inc (ILMN.O) fell as much as 3.5 percent in extended trading Thursday after the maker of tools for genetic analysis reported lower quarterly profit, but still topped the average estimate. [ID:nSGE6130KZ]
* The Obama administration's proposal to limit risk-taking by major banks in the wake of the financial crisis could affect about 10 percent of Goldman Sachs Group Inc's (GS.N) net revenues, a senior company executive told a U.S. Senate committee. [ID:nN04208561]
* U.S. stocks suffered their worst losses in more than nine months on Thursday on fears over euro zone debt and an unexpected rise in U.S. claims for jobless insurance. The S&P 500 .SPX fell 3.1 percent. (Editing by Jeffrey Benkoe)