Wall Street is poised for a lower open on Friday as stocks struggle to make headway despite technical resistance and investors worry about the impact of handling euro-zone debt problems.

U.S. stocks ended 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 1,340 level on the S&P has met with repeated bouts of selling.

We seem to be getting more pressure on that level, but the market is trying to find a balance between what's going on technically and what's going on macroeconomically, said Joseph Greco, managing director at Meridian Equity Partners in New York.

Market sentiment remained fragile due to the debate about possible solutions to Greece's debt problems, with the main market worry that any restructuring could have contagion effects beyond Greece's borders.

Shares in clothing retailer Gap Inc fell 17.9 percent to $19.12 in premarket trade after it slashed its full-year profit outlook late on Thursday, saying higher price tags will not be enough to offset rising cotton costs.

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.

S&P 500 futures fell 2.2 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 19 points while Nasdaq 100 futures fell 5 points.

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.

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)