What's moving markets today

Shares of Twitter (TWTR) are plunging 9% after it revealed it's losing millions of users and providing light guidance for the first quarter of this year.

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The Bank of England has dramatically slashed its forecast for UK economic growth, and now says the British economy will expand by just 1.2% in 2019 because of concerns about Brexit and a slowdown in economic growth.

That is the weakest since the global financial crisis in 2009.

In November, the bank expected the economy would grow 1.7% in 2019.

With Britain set to leave the European Union in just 50 days, the bank said Brexit uncertainties "had intensified considerably" since its last meeting.

“UK economic growth slowed in late 2018 and appears to have weakened further in early 2019,” the bank said in a statement.

“This slowdown mainly reflects softer activity abroad and the greater effects from Brexit uncertainties at home,” it added.

The Bank of England kept interest rates on hold on Thursday, but indicated rates may not rise as fast as it previously anticipated.

The pound took a hit following the announcement. It was trading as much as 0.4% lower against the dollar, at just below $1.29.

Taco Bell's partnership with Grubhub is growing.

The brand said Thursday that it will start delivering nationally through the delivery service.

“We’ve been working towards the moment ... since we first announced our partnership with Yum! Brands last year," said Seth Priebatsch, head of enterprise restaurants for Grubhub, in a statement. Fast food chains are beefing up their delivery options to better reach customers at home and learn more about their preferences.

It seems the effort is working: Taco Bell sales are up. The chain’s parent company Yum! Brands (YUM) said Thursday that global same-store sales grew 6% in the last three months of 2018, compared to the same period a year earlier.

US delivery is just one tactic Taco Bell has used to boost sales. Taco Bell is expanding in Europe, and recently opened four new locations that serve beer in London.

Fiat Chrysler's (FCAU) stock plunged 10% in premarket trading after the automaker posted earnings and revenue growth that fell short of forecasts.

The company said it expects earnings to improve in 2019, but that guidance was also short of Wall Street forecasts.

The company did report increased car sales and profits in North America, outperforming rivals General Motors (GM) and Ford (F), which both reported lower North American sales during the year.

But Fiat Chrysler's annual profits in Europe plunged 45% on flat sales. And the company posted an annual loss in the Asia-Pacific region compared to a profit of a year earlier, because revenue and shipment volume both fell sharply. Industrywide auto sales in China, the world's largest market, fell sharply on a slowing of the economy there.

BB&T (BBT) and SunTrust (STI) banks announced plans to merge, creating the sixth-largest American bank.

The all-stock deal values the merger at $66 billion and is expected to close in the fourth quarter of this year.

"It's an extraordinarily attractive financial proposition that provides the scale needed to compete and win in the rapidly evolving world of financial services," said BB&T CEO Kelly King in a release.

Shares of BB&T are moving 4% higher and SunTrust shares are up 9%.

Shares of Chipotle (CMG) are soaring more than 10% after investors found yesterday's earnings report quite appetizing.

The surge could be attributed to the chain's turnaround under CEO Brian Niccol. His emphasis on digital helped Chipotle grow its digital sales surge 65.6% for the final three months of 2018.

The company also said restaurant sales grew 6.1% and revenue grew 10.4% to $1.2 billion.

CNN Business recently named Niccol its CEO of 2018 for helping turn Chipotle around following an E. coli outbreak that engulfed the chain in late 2015 and early 2016. The stock shot up 40% last year and it's up 20% year-to-date.

Shares of SoftBank Group (SFTBY) spiked nearly 18% in Tokyo on Thursday after the company announced it would buy back as much as 600 billion yen ($5.5 billion) of its own shares in the next year.

The share buyback takes a leaf out of Warren Buffett's playbook. Buffett's Berkshire Hathaway (BRKA) has a policy of buying back its shares if the price falls below a certain level.

Analysts liked the SoftBank move. "We have long argued that Softbank must take cues from Berkshire Hathaway," Atul Goyal, an analyst at investment bank Jefferies, said in a note to clients.

CEO Masa Son wants to transform SoftBank into the world's most powerful tech investment company.

US stock futures are pointing lower.

The Dow Jones industrial average closed down 0.1% on Wednesday. The S&P 500 shed 0.2%, and the Nasdaq dropped 0.4%.

These companies are reporting earnings today: