Updated from 5:59 a.m. EST

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Here are five things you must know for Tuesday, Jan. 17:

1. -- U.S. stock futures were declining but pared earlier losses and European stocks fell as U.K. Prime Minister Theresa May called for a hard Brexit from the European Union that will see Britain leave the single market.

May promised to forge "a new and equal partnership" with the EU.

"Not partial membership of the European Union, associate membership of the European Union, or anything that leaves us half-in, half-out," she said her speech, excerpts of which were released by her office prior to her speaking.

"We do not seek to adopt a model already enjoyed by other countries. We do not seek to hold on to bits of membership as we leave."

Asian markets finished Tuesday's session mixed.

The economic calendar in the U.S. on Tuesday includes the Empire State Manufacturing Survey for January at 8:30 a.m. EST.

New York Federal Reserve Bank President William Dudley will give a speech, "Evolving Consumer Behavior: A view from the Federal Reserve Bank of New York," at the Retail's Big Show 2017 event held by the National Retail Federation in New York, at 8:45 a.m. Federal Reserve Gov. Lael Brainard plans to discuss the impact of fiscal policy on monetary policy at the Brookings Institution in Washington at 10 a.m.

UnitedHealth (UNH - Get Report)  posted fourth-quarter adjusted earnings of $2.11 a share, ahead of estimates of $2.07. The stock rose 2% in premarket trading.

Morgan Stanley (MS - Get Report)  earned 81 cents a share in the fourth quarter, topping analysts' estimates of 65 cents. Shares gained 2%.

Other companies reporting Tuesday include IBM (IBM - Get Report) , Comerica (CMA - Get Report)  , CSX (CSX - Get Report)  and United Continental (UAL - Get Report)  .

2. -- General Motors (GM - Get Report) could announce as early as Tuesday that it plans to invest at least $1 billion across several U.S. factories, according to multiple reports.

The move follows recent criticism from President-elect Donald Trump over the automaker's imports from Mexico.

GM is making the decision for business and not political reasons, a person briefed on the matter told Reuters.

The company will cite a number of new jobs in excess of 1,000 stemming from the investment but doesn't plan to specify which of its factories are in line for more work, one person told The Wall Street Journal.

 
Separately, Trump told two newspapers in Europe that if German carmaker BMW wanted to build a plant in Mexico, it could expect a tax of 35% on the cars it sold to the U.S.

3. -- Hyundai plans to significantly increase its investment in the U.S. while Trump is president and is considering building a new U.S. factory.

Chung Jin Haeng, a president of the world's fifth-largest automotive group, said Hyundai, Kia and their affiliated companies will spend $3.1 billion by 2021 on research and development and maintaining their factories in Alabama and Georgia.

That represents a 50% increase from the $2.1 billion the companies invested in the U.S. in 2012-2016, according to the Associated Press. The increased spending comes mostly from R&D, as the South Korean carmaker invests in artificial intelligence, autonomous driving, environmentally friendly cars and other future technologies.

"We expect a boost in the U.S. economy and increased demand for various models as President-elect Trump follows through on his promise to create 1 million jobs in five years," Chung said, Bloomberg reported. "We will actively consider introducing new models that have increasing demand and profits."

4. --British American Tobacco (BTI)  said Tuesday it reached an agreement to buy the remaining stake of Reynolds American (RAI)  it doesn't already own for just under $50 billion. 

The deal will see BAT pay $29.44 in cash and 0.5260 of an ordinary BAT share for each outstanding Reynolds share, implying a total current value, based on Monday's exchange rate between the dollar and the pound, of $59.64 a share and a total value of $49.4 billion.

"Our combination with Reynolds will benefit from utilizing the best talent from both organisations. It will create a stronger, global tobacco and NGP business with direct access for our products across the most attractive markets in the world," said CEO Nicandro Durante. "We believe this will drive continued, sustainable profit growth and returns for shareholders long into the future."

5. -- Noble Energy  (NBL - Get Report) will buy Clayton Williams Energy (CWEI)  for about $2.7 billion in a cash-and-stock deal.

The deal expands Noble Energy's holdings in the sought-after Permian Basin. 

The merger is expected to close in the second quarter of 2017.

The acquisition provides Noble Energy with 71,000 net acres in the core of the southern Delaware Basin in Reeves and Ward counties in Texas directly adjacent to Noble Energy's existing 47,200 net acres, the company said in a press release.

Houston-based Noble also gains an additional 100,000 net acres in other areas of the Permian Basin, which according to the U.S. Energy Information Administration is the nation's most prolific oil producing area.