Stock index futures pointed to a flat open on Wednesday as continued high oil prices offset strong labor market data a day after a heavy sell-off.

Private employers added 217,000 jobs in February, according to the ADP Employer Services report, far more than forecast. That could be a positive sign for Friday's non-farm payrolls data, though there has been little correlation between the two in recent months.

Energy remained a concern as Libyan leader Muammar Gaddafi launched an offensive against rebels, and two U.S. amphibious assault ships entered Egypt's Suez Canal on their way to the Mediterranean.

Equities have had a strong inverse relationship with oil over the past several weeks on concerns rising prices could slow economic growth. A jump in oil Tuesday led to a heavy equities sell-off.

Crude futures surged 1.5 percent, topping the psychologically key $100 a barrel level.

The ADP is very strong number, but it doesn't change the situation in the Middle East said Andrew Wilkinson, senior market analyst at Interactive Brokers Group in Greenwich, Connecticut. The labor market is recovering, but crude oil will remain the focus.

In an interview with CNBC television, Berkshire Hathaway Inc chairman Warren Buffett said oil disruptions were a rational concern. He also forecast a decline in the unemployment rate through the 2012 elections.

S&P 500 futures fell 0.1 point and were 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 1 points, and Nasdaq 100 futures were unchanged.

Investors will watch Apple Inc shares as the technology giant prepares to unveil the second version of its popular iPad tablet computer, though the longer-term share reaction to the new product may be less robust. The stock was little changed in premarket trading.

Costco Wholesale Corp reported second-quarter earnings and revenue that rose from the prior year, while Staples Inc posted fourth-quarter profit that missed expectations by a penny.

Shares of Costco slid 0.4 percent to $73.35 before the bell, while Staples lost 1.2 percent to $20.60.

PPL Corp

rose 2.4 percent to $25.50 premarket after a deal to buy German utility E.ON AG's UK power networks for $5.6 billion was announced late Tuesday.

JPMorgan upgraded the semiconductor sector, including Texas Instruments Inc , saying an inventory correction was nearing an end. TI shares rose 0.9 percent to $35.32 before the bell.

Concerns about rising oil prices prompted investors on Tuesday to sell stocks and hedge against further declines. The CBOE Volatility Index VIX <.VIX> jumped 14.5 percent on the uncertainty.

(Editing by Jeffrey Benkoe)