U.S. stock index futures fell on Thursday on disappointing earnings from Cisco and Credit Suisse before weekly jobless claims data.

Cisco Systems Inc shares tumbled 9.5 percent to $19.95 in premarket trading a day after the network equipment maker warned about dwindling public spending and reported weaker quarterly margins.

Overseas, disappointing earnings also hurt sentiment, with European shares off nearly 1 percent after bank Credit Suisse missed profit expectations because of debt charges. Its U.S.-traded shares dropped 6.4 percent to $43.65.

Several global earnings reports have taken some air out of the markets' tires, said Andre Bakhos, director of market analytics at Lek Securities in New York.

While there's no cause for concern yet, days like this prompt on-defense sellers to jump; it's an excuse to sell.

S&P 500 futures fell 7.5 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 tumbled 54 points, and Nasdaq 100 futures were off 19.25 points.

The S&P 500 index's chart shows near-term technical support at the 1,313 level, getting stronger near 1,300.

Soft drink and snacks maker PepsiCo Inc

posted a lower quarterly profit, hurt by the weak economy and its shares fell 1.8 percent to $63.29 premarket.

Sprint Nextel posted a 6 percent increase in quarterly revenue and added mobile subscribers for the first quarter in more than three years, sending its shares up nearly 3 percent in early trade.

Expedia Inc , Kraft Foods Inc and Goodyear Tire and Rubber Co are also due to report earnings.

Debt yields rose in indebted European counties on concerns over the lack of a concrete policy to tackle the euro-zone debt crisis. The U.S. dollar rose versus the euro and pulled commodity prices lower.

Weekly jobless claims data, closely followed to track the recovery of the labor market, is due at 8:30 a.m. Economists in a Reuters survey forecast a total of 410,000 new filings for unemployment benefits, compared with 415,000 in the prior week.

At 10 a.m., the Commerce Department releases wholesale inventories for December. Economists forecast a 0.7 percent rise versus a November decrease of 0.2 percent.

Computer security firm McAfee Inc said hackers working in China broke into computer systems of five multinational oil and gas companies to steal bidding plans and other critical proprietary information.

On Wednesday, investors took profits after a recent rise in U.S. stocks, but a late push helped the Dow squeeze out its eighth straight day of gains.

(Reporting by Rodrigo Campos; Editing by Kenneth Barry)