By Sara Sjolin, MarketWatch

Greeks reject terms of bailout package

U.S. stocks were poised to open sharply lower on Monday, with futures in the red after Greeks over the weekend overwhelmingly rejected the terms of a rescue package proposed by its international lenders.

Futures for the Dow Jones Industrial Average lost 141 points, or 0.8%, to 17,508, while those for the S&P 500 index fell 13.80 points, or 0.7%, to 2,055.25. Futures for the Nasdaq 100 index slid 31.25 points, or 0.7%, to 4,397.50.

The declines tracked losses on the European stock markets, where the Stoxx Europe 600 index erased 1.1% to 379.24 and Germany's DAX 30 index tumbled 1.3% to 10,906.76. Asian shares also mostly slumped (http://www.marketwatch.com/story/china-shares-rise-after-beijings-weekend-rescue-2015-07-05).

Greece's rejection of austerity: The global selloff came after more than 61% of Greeks voted "no" (http://www.marketwatch.com/story/in-rebuke-to-europe-greeks-vote-resounding-no-to-bailout-terms-2015-07-05) in Sunday's referendum on austerity measures put forward by the International Monetary Fund and the eurozone as conditions for further bailout aid. The Alexis Tsipras-led government will now try to renegotiate a new bailout package with the lenders, but economists fear the lenders are unwilling accept looser reforms, raising concerns that Greece will exit the euro.

"The outcome of the Greek referendum has significantly increased the risk of Greece leaving the eurozone, which is now by far the most likely outcome," said Erik Nielsen, global chief economist at UniCredit, in a note. "The process may start within days or weeks, but it won't be a smooth ride into a new currency. It'll be chaos with political ramifications."

The euro was also hit hard by the developments (http://www.marketwatch.com/story/euro-falls-against-rivals-as-greek-voters-reject-austerity-demands-2015-07-06) in Greece, changing hands at $1.1079, down from $1.1115 late Friday in New York. The shared currency traded as low as $1.0952 earlier on Monday, according to FactSet.

Greece's stock market, the Athex Composite , remained closed after being shut last week. The country's banks also stayed shuttered.

U.S. data: On a light day for data, the only major release is the ISM non-manufacturing index due at 10 a.m. Eastern Time. Economists polled by MarketWatch expect a reading of 55% for June, down from 55.7% in May (http://www.marketwatch.com/story/ism-services-index-comes-in-below-forecast-for-may-at-557-2015-06-03).

Investors are closely watching data coming out of the U.S. in trying to gauge when the Federal Reserve will hike interest rates. The top-tier nonfarm payrolls report out on Thursday missed analyst expectations (http://www.marketwatch.com/story/us-adds-223000-jobs-in-june-as-unemployment-falls-to-7-year-low-2015-07-02), although it showed unemployment fell to a seven-year low. U.S. stocks were closed for Independence Day on Friday and ended Thursday (http://www.marketwatch.com/story/us-stock-futures-steady-ahead-of-june-jobs-report-2015-07-02) with a second straight week of losses as investors grappled with uncertainty over Greece.

There were no Fed speakers on tap for Monday.

Corporates: A. Schulman Inc. (SHLM) is expected is report fiscal third-quarter earnings of 77 cents a share on revenue of $605.2 million, according to analysts surveyed by FactSet.

Shares in Aetna Inc. (AET) may see active trade after the health insurer on Friday said it would buy Humana Inc. (HUM) for $37 billion, after weeks of merger talks.

Shares in Dollar Tree Inc. (DLTR) are expected to see active trade after the retailer said late Thursday it received Federal Trade Commission clearance to buy Family Dollar Stores Inc. (FDO)

Tesla Motors Inc. (TSLA) shares could see action given the stock is less than 4% from its away from an all-time high of $291.42, set on Sept. 4. Short-interest in the stock is 19.4% of outstanding shares.

Other markets: Crude oil plunged 3.3% to $55.07 a barrel, while gold inched 0.1% higher to $1.164.60 an ounce.

The dollar traded mixed against other major currencies, with the ICE dollar index up 0.1% at 96.15.

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