Stock index futures dipped on Friday, indicating the S&P 500 may snap a three-day win streak after GE and Google results fell short of expectations and as investors eyed Greek debt talks for signs of progress.

Google Inc shares slumped 7.8 percent to $589.73 in premarket trading after quarterly profit and revenue for the No. 1 Internet search engine missed Wall Street expectations on declining search advertising rates.

General Electric Co fell 2.6 percent to $18.65 after the largest U.S. conglomerate reported roughly flat profit from continuing operations, but revenues missed estimates.

Greece and its private bondholders were converging towards a long-awaited debt swap deal, a source said, with private bondholders possibly assuming a real loss of 65 percent to 70 percent. Hopes are that an agreement would prevent the nation from spiraling into bankruptcy and bring some stability to the debt-strained euro zone.

We are now debating again how much of a haircut the bondholders of Greece are going to take and that is not happy news, said Kim Forrest, senior equity research analyst at Fort Pitt Capital Group in Pittsburgh.

That being said, let's see where things end up today because I thought at least three of the four tech companies had really good and strong results.

A strong outlook from International Business Machines Corp and decent results from Intel Corp and Microsoft Corp signaled that corporate leaders were shaking off nervousness about economic growth and boosting technology spending.

Microsoft shares were up 2.7 percent to $28.89, and Intel edged up 0.7 percent to $25.80 premarket. IBM gained 2.7 percent to $185.38.

The revenue is probably the most concerning thing. They are a bellwether and we are really interested to see what they see, especially in their industrial area, how the orders are, said Forrest.

S&P 500 futures fell 3.4 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 were off 14 points, and Nasdaq 100 futures added 3.25 points.

European shares slipped 0.3 percent early Friday after hitting 5-1/2 month highs in the previous session as major indexes neared overbought territory. Asian shares rose to fresh two-month highs as solid euro zone sovereign debt sales. <.EU>

Economic data on existing home sales was due from the National Association of Realtors for December at 10 a.m. (1500 GMT). Economists forecast a 4.65 million annual rate in December, versus 4.42 million in November.

Chinese factory activity likely fell for a third successive month in January, an early indicator showed, suggesting Beijing's pro-growth policies will remain in place despite early signs a downward drift was slowing.

U.S. stocks rose Thursday, sparked by results from Bank of America Corp and Morgan Stanley and as the latest jobless claims dropped to a near four-year low.

(Reporting By Chuck Mikolajczak; editing by Jeffrey Benkoe)