1. Shutdown for Christmas? Republicans scored a big win this week by passing a sweeping overhaul of the U.S. tax system.

But they'll need to act quickly to avoid a government shutdown.

Congress must pass a stopgap funding bill before midnight on Friday, or risk an embarrassing closure of government agencies.

Republicans in the House and Senate -- who have competing legislative priorities -- were still at loggerheads over a potential deal on Wednesday evening.

One potential outcome is another short-term budget extension that will keep funding at current levels.

2. Election in Catalonia: The Spanish autonomous region of Catalonia will choose a new local government on Thursday.

The vote was called in October when Madrid took control the Catalan government after lawmakers there made a unilateral declaration of independence.

The saga has taken a toll on Spanish markets and revived fears about the stability of the eurozone.

3. Brexit weakness: The number of cars manufactured in Britain fell 4.6% in November, according to the Society of Motor Manufacturers and Traders.

Domestic demand for cars declined more than 28% from the previous year, while exports rose 1.3%.

The industry group blamed a lack of clarity over Brexit for the weakness.

The British government has not said what kind of a trade deal will it seek with the EU -- its biggest trading partner -- after it leaves the bloc in March 2019.

4. Global market overview: U.S. stock futures were flat.

European markets opened lower, while Asian markets ended mixed.

U.S. markets closed slightly lower on Wednesday. The Dow Jones industrial average and the S&P 500 shed 0.1%, while the Nasdaq was little changed.

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5. Earnings and economics: CarMax, ConAgra and Finish Line will publish earnings before the open. NIKE will follow after the close.

The final estimate of third quarter U.S. GDP will be released at 8:30 a.m. ET. Economists are expecting growth of 3.3%.

U.S. data on initial claims will be published at the same time.

The Bank of Japan left key interest rates unchanged at its meeting.

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6. Coming this week:
Thursday -- Nike earnings; Final estimate on 3Q U.S. GDP
Friday -- El Gordo lottery in Spain