Stock index futures rose on Wednesday, indicating stocks will climb for a fourth straight session as investors remained encouraged by progress toward plans to ease the euro zone's debt woes.

International auditors headed to Greece to scrutinize new austerity measures they must endorse for Athens to get their next tranche of aid.

German Chancellor Angela Merkel suggested that parts of a planned new 109-billion-euro ($148.6 billion) rescue for the debt-laden country could be reopened, depending on the outcome of the audit.

Recent efforts to solidify a euro zone rescue fund and alleviate the region's sovereign debt crisis lifted stocks on Tuesday for a third consecutive session and came after four straight days of losses for the benchmark S&P 500.

The market is obviously enthusiastic about some of the measures and actions being taken to stave off a contagion in the euro debt situation, said Andre Bakhos, director of market analytics at Lek Securities in New York.

While the bulls are excited about this in pricing to perfection a successful execution of whatever plan there is, the downside risk is great and volatility is here to stay.

Market volatility could remain as traders react to European headlines and attempt to gauge the commitment of governments and institutions as they work to prevent a Greek default.

Analysts also said equities would be supported by quarter-end window dressing, when portfolio managers drop underperforming stocks and buy outperformers.

S&P 500 futures rose 6.5 points and were above 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 gained 64 points, and Nasdaq 100 futures added 14 points.

Investors will also eye data on August durable goods orders from the Commerce Department, due at 8:30 a.m. EDT. (1230 GMT) Economists in a Thomson Reuters survey expected orders to be unchanged in August versus a 4.1 percent rise in July.

In early earnings reports, spicemaker McCormick & Co Inc posted a quarterly profit that topped estimates, while discount chain Family Dollar Stores Inc recorded higher quarterly earnings. Darden Restaurants Inc was scheduled to report later Wednesday.

Asian shares mostly lost ground and oil and metals fell, with copper down more than 4 percent, as a rebound in riskier assets ran out of steam.

(Reporting by Chuck Mikolajczak; editing by Jeffrey Benkoe)