Stocks traded mostly lower Monday with the Dow Jones Industrial Average taking a pause in its race toward 20,000.

The S&P 500 was down 0.15%, and the Dow slid 0.17% to 19,930, while the Nasdaq rose 0.13%.

Dow 20,000 came agonizingly close on Friday, but building momentum flagged in the final moments to fall short of the milestone. The Dow came within a point of the level in the afternoon session before backing off, just as it has for weeks. The S&P 500 and Nasdaq each closed at fresh records on Friday.

Crude oil prices fell below $53 a barrel on Monday, continuing to trade off of data late Friday that showed rising U.S. production. A weekly reading on U.S. activity showed the number of U.S. oil rigs climb for the 10th consecutive week in a row.

Commodities trading has been erratic in the past week as investors weigh U.S. production against an agreement among major oil-producing nations designed to rebalance markets. A production cut agreement among Organization of Petroleum Exporting Countries and other non-OPEC producers took effect at the beginning of the year.

West Texas Intermediate crude was down 2.5% to $52.63 a barrel on Monday morning.

The energy sector was the worst performer on Monday. Major oilers including Exxon Mobil (XOM - Get Report) , Chevron (CVX - Get Report) , Halliburton (HAL - Get Report)  and Marathon Petroleum (MPC - Get Report) slid, while the Energy Select Sector SPDR ETF (XLE - Get Report) fell 1.3%. 

The U.S. economy warrants "somewhat more regular" interest rate hikes, Boston Federal Reserve President Eric Rosengren said on Monday. In a speech in Hartford, Conn., Rosengren said the "economic circumstances have evolved and now imply the need for a different stance of monetary policy." Rosengren is a voting member of the Federal Open Market Committee this year.

The British pound tumbled more than 1% overnight after British Prime Minister Theresa May suggested a full withdrawal from the European Union, conflicting with a former ambassador to the EU who had suggested the approach so far had been "muddled." May told Sky News that the U.K. would no longer be a member of the EU and that she would provide "more details in the coming week as we look ahead to triggering Article 50."

Pet health care company VCA (WOOF) agreed to be acquired by Mars Inc. on Monday in a deal worth $9.1 billion. Snacks and petcare company Mars agreed to purchase VCA for $93 a share, a roughly 31% premium to its close on Friday. The deal is slated to close in the third quarter of this year. VCA shares jumped 28%.

Ariad Pharmaceuticals (ARIA) surged 73% after Takeda Pharmaceutical agreed to acquire the drugmaker in a deal worth $5.2 billion. Takeda offered to purchase Ariad for $24 a share, valuing the drugmaker at a premium of 75% compared to its closing price on Friday of $13.74. The all-cash deal is expected to close by the end of February.

Urban Outfitters (URBN - Get Report) fell 1.9% after reporting same-store sales over the critical holiday shopping season. Total same-store sales climbed 1.5%, which was less than expected. Same-store sales at its Urban Outfitters stores increased 3.6%, while Anthropologie sales declined 1%.

Acuity Brands (AYI - Get Report)  declined 13% after soft demand crimped quarterly growth over the three months ended November. The lighting company earned adjusted profit of $2 a share, up from $1.77 a share a year earlier. Analysts had anticipated profit of $2.16 a share. Revenue rose 16% to $851.2 million, though fell short of $894.94 million consensus. 

Global Payments (GPN - Get Report) added more than 7% after increasing its fiscal 2017 earnings guidance. The check processing company expects to earn an adjusted $3.70 to $3.90 a share over the full year. The company had previously anticipated adjusted earnings of $3.45 to $3.55 a share. 

Francesca's Holdings (FRAN - Get Report) climbed 8% after upping its fourth-quarter outlook. The retailer anticipates earnings for its January-ending quarter between 35 cents and 37 cents a share. Francesca's had previously targeted 33 cents to 37 cents a share. Its fourth-quarter same-store sales outlook was also revised from an expected 1% decline to expected 1% growth.

Fiat Chrysler (FCAU - Get Report) added 1.5% after outlining plans to invest $1 billion in plants in Michigan and Ohio, adding 2,000 new jobs to the U.S. The move comes after President-elect Donald Trump took aim at a number of automakers via Twitter in which he criticized any plans to ship jobs out of the U.S. and threatened to impose border taxes.

Merrimack Pharmaceuticals (MACK)  was 5.3% higher after drugmaker Ipsen agreed to buy some of its assets, including its drug for pancreatic cancer, in a deal worth more than $1 billion. Merrimack also said it would eliminate about 80% of its staff as it refocuses its pipeline.

Texas Instruments (TXN - Get Report) was upgraded to outperform from neutral at Credit Suisse. The firm said earnings estimates are above consensus given higher sales and margin expectations.

Coca-Cola (KO - Get Report) was downgraded to sell from neutral at Goldman Sachs. Analysts pointed to structural changes and increased challenges over currency as reasons for the downgrade. Dr. Pepper Snapple  (DPS) was upgraded to neutral given its higher exposure to the U.S. market. 

McDonald's (MCD - Get Report)  slipped after selling a majority stake in its operations in China to Carlyle Group (CG - Get Report) and a state-backed investment group for around $2.1 billion. The agreement would see McDonald's part with 80% of its 2,200 stores in China and Hong Kong. The world's largest hamburger chain intends to keep a minority stake in the region.