NEW YORK (TheStreet) -- Here are 10 things you should know for Tuesday, Dec. 30:

1. -- U.S. stock futures were looking weak on Tuesday. The S&P 500 was down by 0.23% in premarket trading, and the Nasdaq was down by 0.12%. The Dow was dropping by 0.11%.

European stocks were tumbling as a weak energy sector and upcoming Greek elections shook investor confidence on the last full day of trading for European markets this year. In London, the FTSE 100 was down 0.57% at 6,596.03. The CAC 40 in Paris dropped 0.69% to 4,288.32. And in Frankfurt the DAX fell 0.64% to 9,863.94.

Asian stocks were also declining on Tuesday. The Nikkei fell 1.57% to 17,451 in Tokyo and the Hang Seng dropped 1.14% to 23,501.10 in Hong Kong.

2. -- The economic calendar in the U.S. on Tuesday includes data from the S&P Case-Shiller Home Price Index, which tracks residential real estate prices, at 9 a.m. Consumer Confidence Index numbers are released at 10 a.m.

3. -- U.S. stocks on Monday closed mixed. The Dow (DIA) sank 0.09% to close at 18,038.23. The S&P 500 (SPY) added 0.09%, ending the session at 2,090.57, a new high. The Nasdaq (QQQ) closed flat at 4,806.91. And the Russel 2000 rose 0.32% to 1,219.11.

4. -- Upcoming Greek elections are making European investors nervous, as Prime Minister Antonis Samaras failed to get support for his presidential candidate. Greece's left-wing opposition party Syriza looks well-positioned for the elections.

A victory by Syriza might upend Greece's austerity program. The effects of the election on economic stability in Greece and in Europe are difficult to predict.

5. -- Debris from the wreckage of a missing AirAsia flight was found near Borneo. There appear to be no survivors among the 162 passengers.

AirAsia as yet had no explanation for why the flight vanished and then crashed into the ocean.

6. -- UPS (UPS) and FedEx (FDX) delivered 98% of packages on time for the Christmas holiday last week, said tracking-software maker Shipmatrix. The companies had limited their delivery promises in advance of the holiday in the hopes of avoiding last year's late-delivery problems.

7. -- Oil prices are down 50% since June. Tuesday crude oil futures were dropping to new five-year lows.

Despite trouble in Libya and some idled rigs in the U.S., there's no sign yet of an end to the ongoing oil glut. U.S. oil output is greater than it has been in 30 years, while OPEC is avoiding cutting back on production.

8. -- Chinese citizens are buying into the stock market in a new rush. With a slowing economy and a weakening real estate market, China's stock market seems more appealing as an investment, the New York Times reports.

Markets in Shanghai and Shenzhen are surging, with plenty of new money from new investors at play. Shanghai's index is up 50% this year alone.

9. -- The IRS will begin accepting 2014 tax returns on Jan. 20, it announced, despite delays from Congress on enacting year-end tax changes. The new Affordable Care Act recordkeeping may make filling more complicated for some taxpayers this tax year, as will new regulations on foreign accounts.

Congress recently cut the IRS's budget by $346 million.

10. -- Wednesday is the final trading day of the year. Investors should set up any tax-loss harvesting or year-end moves now.

-- Written by Nora Morrison

Follow @NoTicker

Nora Morrison is an editor, writer and researcher on music, popular culture and business. She is an associate editor at TheStreet, and is on Twitter at No Ticker.

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