Stock index futures rose on Wednesday as continued strong earnings, including from Apple Inc , underscored the growing sense companies were faring well despite the recent soft patch in the economy.

Equities have struggled against a number of headwinds recently, including weak data on the U.S. labor market and concerns about sovereign debt problems in the United States and Europe. On Tuesday, however, strong results from such bellwethers as International Business Machines Corp and Coca-Cola sparked Wall Street's best day since March.

Just about everyone who has reported results has beaten expectations, and that's enough to offset the global macro headwinds that are out there, said Jack De Gan, chief investment officer at Harbor Advisory Corp in Portsmouth, New Hampshire.

This market is all about earnings, and its relieving the concerns out there about the temporary weakness in the economy and about valuation.

Tech giant Apple reported after Tuesday's close that it posted third-quarter revenue that was far above expectations, helped by blockbuster sales of its iPhone and its Asian business. The stock gained 5.9 percent to $398.98 in premarket trading.

Among the early reporting companies on Wednesday was Dow component United Technologies Inc , which raised its full-year profit view. Textron Inc reported a second-quarter profit that beat expectations.

Shares of Textron rose 2.8 percent to $22.75 before the bell while United Tech was up 1.6 percent to $90.25.

Apart from earnings, AMR Corp , the parent company of American Airlines, rose 3.4 percent to $5.15 in premarket trading after the company said it plans to buy 460 narrowbody Boeing Co 737s and Airbus EADS A320s beginning in 2013. Boeing shares rose 1.4 percent to $71.50.

Also, Ecolab Co said it would buy Nalco Holding Co for $5.4 billion, sending shares of Nalco up 31 percent to $37.85.

S&P 500 futures rose 7.4 points and were above 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 added 62 points and Nasdaq 100 futures rose 21.5 points.

Yahoo Inc late Tuesday reported a slight decline in net revenue in the second quarter, as efforts to restructure its sales force caused disruptions that crimped revenue.

Among the many companies still due to report earnings on Wednesday are American Express Co and Intel Corp .

Investors will also be looking at June existing home sales data, which are due 10:00 EDT and are seen rising from the previous month. On Tuesday, housing starts that were much stronger than expected contributed to the market's positive tone.

The growing optimism over earnings season comes as market participants also gain more confidence in the talks for a debt deal in the United States. Markets gained momentum late in the day on Tuesday after President Barack Obama suggested progress was being made toward a $3.75 trillion deficit reduction deal centered around entitlement reform.

The White House and Congress need an agreement that includes an increase in the federal debt ceiling by August 2 or the United States could default on its debt.

Obama's comments, along with the earnings, sparked a sharp equity rally on Tuesday, with all indexes rising more than 1.6 percent and the Nasdaq climbing more than 2 percent.

(Editing by Chizu Nomiyama)