U.S. stock index futures were mixed on Wednesday with Nasdaq lifted by blowout profits from Apple as the focus shifted to results from four Dow components and other bellwethers including Morgan Stanley.

Apple Inc shares hit an all-time high in late trading on Tuesday after its quarterly results blew past expectations on the back of record iPhone sales, and the company gave a strong revenue forecast. Shares rose 5.9 percent to $259 in premarket trading on Wednesday.

Apple certainly was a big number last night, and I think it will give a positive tone, certainly to the Nasdaq, all day, said Rick Meckler, president of investment firm LibertyView Capital Management in New York.

S&P 500 futures fell 2.6 points but were slightly 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 34 points, and Nasdaq 100 futures added 4.5 points.

Dow component United Technologies Corp posted a 20 percent rise in profit, ending a four-quarter streak of declines. Its shares closed at $74.20 on Tuesday.

Dow components Boeing Co and AT&T Inc reported results early Wednesday. Also due is McDonald's Corp .

Morgan Stanley is due to report first-quarter results, with analysts looking for a profit of 57 cents per share, according to Thomson Reuters I/B/E/S. The results will be the first under new Chief Executive James Gorman and his reshuffled management team.

Other companies due to report include Wells Fargo & Co , Freeport-McMoRan Copper & Gold Inc and eBay Inc .

Meckler said the market doesn't see a lot of obstacles but has already come a long way, and the mix of profit-taking and anticipation to better results is leading to mixed markets in the mornings.

Wednesday's earnings and outlooks, which include a cross-section of companies in several industries, will give investors a reading on the extent of an economic recovery.

Yahoo Inc shares fell 3.2 percent to $17.80 premarket, a day after it recorded revenues shy of estimates, with search advertising revenue off 14 percent. The company said net revenues could miss the average view next quarter.

The International Air Transport Association estimated the shutdown of most European airports caused by a volcanic ash cloud cost airlines more than $1.7 billion in revenues.

U.S. stocks rose on Tuesday as oil prices lifted energy shares and investors were upbeat about the overall corporate profits recovery, even as some the results of some high-profile companies fell short of lofty expectations.

(Editing by Jeffrey Benkoe)