By Barbara Kollmeyer, MarketWatch

MADRID (MarketWatch) -- U.S. stock futures traded flat Tuesday ahead of a batch of earnings -- J.P. Morgan Chase & Co. and Citigroup Inc. included -- with investors wary after late-session selling Monday pushed major indexes sharply lower.

Futures for the S&P 500 index (SPZ4) rose 4 points to 1,866.90, while those for the Dow industrials (DJZ4) were flat at 16,230. Futures for the Nasdaq 100 index (NDZ4) gained 3 points to 3,803. Stock futures erased some gains after downbeat German sentiment data.

Extending last week's losses, volatile trading on Monday ended with the S&P 500 (SPX) dropping 1.6% to 1,874.74. Like other major benchmarks, the S&P 500 is now trading below its 200-day moving average of 1,900. Vote here: Does this stock slump have further to go?

James Hughes, chief market analyst for Alpari U.K., said he's wary because he sees traders targeting old stories, such as concerns over slow global growth and its effect on earnings. "When traders look for excuses for why the market is falling, [it] is always a worrying time and would point to me as an indication that we could see much more negativity to come," he said in a note.

Earnings in focus: The tide could change with Tuesday's earnings batch, the first busy day in the third-quarter reporting season. Ahead of the bell, J.P. Morgan Chase & Co. (JPM) is expected to report per-share earnings of $1.38 on revenue of $24 billion, according to analysts surveyed by FactSet.

Citigroup (C) is expected to report per-share earnings of $1.12 on revenue of $19.16 billion.

Wells Fargo & Co.(WFC), Domino's Pizza Inc. (DPZ) and Johnson & Johnson (JNJ) are among the other names reporting.

Among other stocks in focus, Versar Inc. (VSR) was surging in early premarket trading. Its PPS unit makes hazmat suits and mobile decontamination shelters. Other stocks linked to concerns over the Ebola virus continued a pattern of pushing higher. Lakeland Industries Inc. (LAKE) and Alpha Pro Tech Ltd. (APT) were trending higher. Ebola stock trading volumes should raise red flags

Other markets: European stocks fell after the German ZEW sentiment survey turned negative. Burberry Group PLC shares dropped after the luxury-goods maker posted a rise in sales, but cited unfavorable foreign exchange headwinds and Chinese weakness. U.K. inflation fell to a five-year low. The European Court of Justice has begun holding a hearing on the European Central Bank's Outright Monetary Transactions bond-buying program. In Asia, the Nikkei 225 index sank 2.4%, falling below the 15,000 level and skidding to two-month lows.

Crude-oil prices(CLX4) drifted lower, and gold(GCZ4) inched up, while the dollar ((USDJPY) pulled back from an overnight slip against the Japanese yen.

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