Stock index futures fell on Friday as Wall Street faced technical resistance after shares rose two days in a row.

Shares in clothing retailer Gap Inc will be under pressure after it slashed its full-year profit outlook on Thursday, saying higher price tags will not be enough to offset rising cotton costs.

Merger and acquisition activity could influence shares. The stock of Barnes & Noble Inc was up 29.3 percent at $18.24 in premarket trade after John Malone's Liberty Media Corp proposed buying the company for $1.02 billion. The largest U.S. bookstore chain put itself up for sale nine months ago.

It looks to be a light trading day with sideways movements, but we may see some support from this M&A action after the open, said Peter Cardillo, chief market economist at Avalon Partners in New York.

S&P 500 futures fell 4.9 points and were below fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration of the contract. Dow Jones industrial average futures lost 40 points while Nasdaq 100 futures fell 9 points.

U.S. stocks edged higher on Thursday but the S&P 500 ran into resistance after its recent bounce, and many investors expect a patch of economic weakness over the summer.

The S&P is struggling to make headway above 1,340, an area that has met with repeated bouts of selling.

Big outflows from equity exchange-traded funds overwhelmed actively managed stock mutual funds in the week ended May 18, while municipal bond funds extended their outflow streak, data from Thomson Reuters Lipper showed on Thursday. Overall, U.S.-domiciled equity funds suffered nearly $6 billion in net outflows, with the vast majority coming out of domestic-focused equities.

BP struck a key victory in its battle to share the cost of the Gulf of Mexico oil spill when partner Mitsui & Co agreed on Friday to pay $1.1 billion toward the clean-up bill and possibly billions more in fines.

Oil prices recovered on Friday as traders seized the previous session's dip as a chance to snap up cargoes amid expectations that the concerns over supply disruptions in the Middle East and North Africa would continue to support the market.

(Reporting by Angela Moon, Editing by Kenneth Barry)