U.S. stocks were poised for a flat to higher open on Friday as investors sought to determine whether a pullback is on the horizon after a 6-month rally and braced for options expiration.

Analysts said investors were trying to decide if further market gains were justified, with the benchmark S&P 500 now up 58 percent since early March lows.

The real question is are we looking good enough to validate these prices, said Frank Lesh, a futures analyst and broker at FuturePath Trading LLC in Chicago.

A correction will be inevitable ... The markets are getting into overbought territory, the rate of advance is slowing, so there are some signs.

S&P 500 futures rose 2.5 points and were slightly 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 jumped 45 points, and Nasdaq 100 futures added 5 points.

Friday marks the quarterly expiration and settlement of four different types of September equity futures and options contracts -- a convergence known as quadruple witching that can lead to greater volume and volatility as traders unwind positions.

Procter & Gamble Co
shares rose 1.7 percent to $56.45 after Citigroup upgraded the stock to buy from hold, saying investors will warm up to the new fire in the P&G's belly.

Chevron Corp gained 0.8 percent to $72.47 after Credit Suisse upgraded the stock to outperform from neutral but said it expects major U.S. and European integrated oil companies to struggle to boost production to 2020.

Palm Inc
fell 1.7 percent to $14.20 after the company gave a tepid second-quarter sales forecast and said it plans to sell more shares, even as it reported a smaller-than-expected loss due to sales of its new Pre smartphone.

Boeing Co will garner attention after the head of Airbus said in remarks in the Wall Street Journal Friday that the European planemaker faces two further difficult years and does not rule out making more production cuts to adjust to demand.

(Reporting by Chuck Mikolajczak; editing by Jeffrey Benkoe)