Thank you for joining us on Business Live.
We will be back from 6.00am on Tuesday with all the breaking business news.
Thank you for joining us on Business Live.
We will be back from 6.00am on Tuesday with all the breaking business news.
At the end of a turbulent day of trading, Facebook's share price closed down 6.77% at $172.56.
The Nasdaq finished down 137.74 points at 1.84%.
The Dow Jones Industrial Average ended 335.60 points lower at 24,610.91.
The S&P 500 closed 39 points lower at 2,712.92.
The Wall Street Journal is reporting that oil giant Saudi Aramco is likely to list solely in Saudi Arabia next year and will take more time to decide if it will go ahead with an international listing.
What a day for the US markets.
Out of the 30 stocks traded on the Dow Jones Industrial Average, 29 closed down.
And of the S&P 500's index, some 452 finished lower.
Facebook's stock has regained a little ground but not much - its shares are down 6.90% at $172.32.
Jennifer Sireklove, director of responsible investing at Parametric, a Seattle-based group with $200bn in assets, says that some clients are reluctant to invest in social media and internet companies.
"More investors are starting to question whether these companies are contributing to a fair and well-informed public marketplace, or are we becoming all the more fragmented because of the ways in which these companies are operating," she says.
Commenting on the sharp fall in US technology stocks on Monday, led by Facebook, Eric Freedman, chief investment officer at US Bank Wealth Management: "Everyone knows that tech fundamentals are solid, but rumblings like what you are seeing today, that does sort of prompt people to think is this as good as it is going to get or should I take some profits here."
Facebook says it is "moving aggressively to determine the accuracy" of claims that the profiles of 50 million users was harvested to build profiles of potential voters.
It says: "We also want to be clear that today when developers create apps that ask for certain information from people, we conduct a robust review to identify potential policy violations and to assess whether the app has a legitimate use for the data. We actually reject a significant number of apps through this process."
It adds: "Kogan’s app would not be permitted access to detailed friends’ data today."
More from Facebook...
The firm it has hired to conduct an audit of Cambridge Analytica is called Stroz Friedberg.
It also says it has approached "other parties involved" Christopher Wylie and Aleksandr Kogan to ask them to submit to an audit as well.
"Mr Kogan has given his verbal agreement to do so. Mr. Wylie thus far has declined."
CNBC reports that Facebook has hired a digital forensics firm "to conduct a comprehensive audit of Cambridge Analytica".
Volvo confirmed that a Volvo XC 90 was involved in the fatal Uber crash.
It adds: "This was not Volvo's self-driving technology."
Facebook's shares are now down 7.32% at $171.55.
The technology-focused Nasdaq remains in the doldrums, down 2.38% or 178.29 points at 7,303.70.
The Dow Jones Industrial Average is down 1.75% or 436.51 points at 24,510.00.
The S&P 500 has fallen 1.69% to 2,705.43.
Within less than two decades it will be cheaper to operate robots in US factories than hire workers in Africa, a new report warns.
Falling automation costs are predicted to cause job losses as manufacturers return to richer economies.
Some analysts say poorer countries could be less impacted by this trend, however the Overseas Development Institute suggests otherwise.
Here's a UK stock to watch out for in Tuesday morning trade - industrial materials group Fenner.
Michelin, the French tyre-maker, has just announced that it has agreed a deal to buy the British engineering firm that makes conveyor belts for the mining sector in a deal valued at £1.3bn.
Shares in Fenner rose 5.14% to 490.60p earlier today.
It also happens to be the second engineering company in a takeover situation - GKN is the subject of a hostile takeover bid by turnaround firm Melrose.
Michelin's chief executive Jean-Dominique Senard, says: "Mastering high-technology materials is key to creating value in the coming years. Fenner will enable Michelin to accelerate its growth in this area, and to strengthen its position as a key player in the recovering mining markets with a comprehensive offering.”
Cambridge University has issued a statement on Dr Alex Kogan who is accused of misusing users' data from Facebook.
It says that Dr Kogan is no longer a lecturer, but rather is a senior research associate in the Department of Psychology at the university.
It says that "it is not uncommon for Cambridge academics to have business interests" as long as they are held in a personal capacity and there are no conflicts of interest.
Cambridge University says it had "previously sought and received assurances from Dr Kogan that no university data, resources or facilities were used as the basis for his work with Global Science Research or the company’s subsequent work with any other party".
It says: "We have to date found no evidence to contradict Dr Kogan’s previous assurances. Nevertheless, we are writing to Facebook to request all relevant evidence in their possession."
It adds: "Researchers are also permitted to undertake academic research outside the university provided it does not interfere with the performance of their duties. We understand that Dr Kogan correctly sought permission from his head of department at the time to work with St Petersburg University; it was understood that this work and any associated grants would be in a private capacity, separate to his work at the University of Cambridge."
The stock market rout in the US appears to be gathering speed.
The Dow Jones Industrial Average has now fallen 455.66 points, or 1.83%, to 24,490.85.
The Nasdaq is now down 2.11%, or 157.63 points, at 7,324.36 as concerns about how users's data is used moved from Facebook to Amazon, Apple, Netflix and Google-owner Alphabet - who make up the FAANG group of companies.
Shawn Cruz, senior trading specialist at TD Ameritrade, said: "Tech companies all use data one way or the other as part of their businesses. They are going to get a lot more scrutiny over what data they are collecting and how they are using it.
"That's dragging a lot of those FAANG stocks down because at the end of the day, really what a lot of those companies did is they were taking a lot of data and using algorithms to dial in their product."
The US owner of Claire's Accessories has filed for bankruptcy protection in a bid to cut its $1.9bn (£1.3bn) debt pile.
Claire's Stores said its shops, including 378 in the UK, will stay open as it presses ahead with a financial restructure.
The company is owned by private equity firm Apollo Global Management, which paid $3.1bn for it in 2007.
Ron Marshall, Claire's chief executive, said: "We will complete this process as a healthier, more profitable company, which will position us to be an even stronger business partner for our suppliers, concessions partners, and franchisees."
Channel 4 has revealed a pay gap of 28.6% between the men and women who work for the broadcaster.
The gap is above the the national average of 17.4% despite Channel 4's workforce being comprised of 59% women.
Last week, media company ITN said there was a 19.6% within its staff while the BBC disclosed a 10.7% gap.
Channel 4 says the discrepancy is down to there being a large number of women in the lower two quartiles at the organisation, and the majority of positions in the highest-paid quartile being filled by men.
Its chief executive Alex Mahon says she is "not happy" about the gap and she is "determined to take action".
The gathering storm over how millions of Facebook profiles were apparently exploited for political purposes raises all sorts of questions about how our data is used.
But already some in the data and marketing industries are pouring cold water on the story which the Guardian's Carole Cadwalladr has pursued with such admirable vigour.
"Nothing very new here," they say with a world-weary sigh. "This sort of thing has been going on for years." But that surely is the point - we are finally waking up to a murky world where there is little regulation, and companies can trade our personal information without a care.
BT will close its defined benefit pension scheme after striking an agreement with the Communication Workers Union on the future arrangements for 20,000 staff.
The telecoms giant said it expected to close its scheme, one of the UK's biggest, to future benefits on 31 May 31 - but some administrative-related issues were still outstanding.
BT and the CWU have agreed to work together to establish a new "hybrid" pension arrangement over the coming year for team members leaving the scheme, combining elements of both defined benefit and defined contribution pension schemes.
"These changes bring far more financial certainty for the company in terms of our future pension arrangements," said chief executive Gavin Patterson.
What is driving US stocks lower?
The US Federal Reserve is widely expected to lift interest rates to 1.75% when it meets - for the first time under new chairman Jerome Powell - on Wednesday.
Rick Meckler, president of investment firm LibertyView Capital Management, says: "I don't think anyone's expecting any surprises (from the Fed) ... but the bigger factor has been the surrounding the big technology companies, particularly Facebook.
"Just a re-examination of whether or not there are issues out there for all of the tech companies, regulatory or otherwise. They've been such leaders that it's spilling over into the general markets."
The other main indexes on Wall Street are also down with the Nasdaq plunging 1.56% or 116.46 points at 7,365.17.
The S&P 500 is off 26.71 points or nearly 1% at 2,724.99.
Republicans and Democrats are calling on Facebook chief executive Mark Zuckerberg to testify before Congress following claims that details from 50 million profiles were gathered without consent.
In a joint letter, Republican Senator John Kennedy and Democratic Senator Amy Klobuchar asked Senate Judiciary Chairman Chuck Grassley to hold a hearing with Mr Zuckerberg and as well as with the chief executives of Google and Twitter.
They said: "Facebook, Google, and Twitter have amassed unprecedented amounts of personal data and use this data when selling advertising, including political advertisements.
"The lack of oversight on how data is stored and how political advertisements are sold raises concerns about the integrity of American elections as well as privacy rights."
The Dow Jones Industrial Average has now fallen 254.41 points, down 1%, to 24,692.10.
Mike Cherry, national chairman of the Federation of Small Businesses, says the Brexit transitional deal gives small firms "some certainty" and protects it "from a damaging cliff-edge moment".
He says: "The offer of permanent residency to EU citizens arriving during the transition period is good to see. Equally, small business owners and the self-employed will welcome the freedom to freely cross European borders after 2019. Losing that freedom can mean losing out to European competitors."
He adds: “It’s encouraging to see so much of the withdrawal agreement green lit. We look forward to seeing some more certainty around the shape of final Brexit terms, including proposals for avoiding a hard border between Northern Ireland and the Republic.”
What a day it has been for Micro Focus. Its share price is now down 42.18% to 15.16p
Here's what the share price graphic looks like:
Antony Walker, deputy chief executive of techUK, the tech trade association, welcomed the transition deal but says: "Both sides should not be complacent having formalised a transition period and must now ensure we have not simply kicked the can down the road leaving a Brexit cliff edge on New Year’s Day 2021."
He adds that the sector is concerned that "there remains no formal agreement around the ongoing ability to deliver the free flow of data during the transition period".
"It needs to be clear that the UK is not a ‘third country’ when it comes to free flow of data during the transition."
The CBI says that the Brexit transition deal delivers a "gift of time and victory for common sense".
Carolyn Fairbairn, director-general of the business lobbying group (pictured), says: "Agreeing transition is a critical milestone that will provide many hundreds of businesses with the confidence to put their contingency planning on hold and keep investing in the UK."
She adds: "A year ago both sides ruled out an early transition deal; today both sides have agreed one. The voice of prosperity and evidence from the business community is being heard. This spirit of compromise must be maintained, as tough choices lies ahead on the route to a final deal."
The Dow Jones Industrial Average is trading down 194.15 points or 0.78% at 24,752.36.
The S&P 500 is off 16.12 points, or 0.59%, at 2,735.89.
The Nasdaq is 70.49 lower, down 0.94%, at 7,411.49.
Ian Wright, head of the Food and Drink Federation, is not quite as enthusiastic about today's announcement on the transition period:
Food and drink manufacturers are now looking for serious reassurance from government that will not press ahead at any economic cost and that they will be flexible if systems - particularly customs - are not ready in 21 months' time. Similarly, negotiations must avoid a hard border on the island of Ireland, where ingredients, finished products and workers cross the border many times a day. Until the appropriate technological solutions can be found, then the option of a regulatory backstop must be left on the table."
Shares in Facebook fell by 4.78% to $176.24 in the first minutes of trade on Monday.
It following reports over the weekend that users' profile information may have been obtained and kept by Cambridge Analytica, a data firm widely-credited with helping Donald Trump win the 2016 US presidential election.
Adam Marshall, chief of the British Chambers of Commerce, says it is a "milestone" that many UK businesses have been waiting for.
"The agreement of a status quo transition period is great news for trading firms on both sides of the Channel, as it means that they will face little or no change in day-to-day business in the short-term," he says.
“While some companies would have liked to see copper-bottomed legal guarantees around the transition, the political agreement reached in Brussels is sufficient for most businesses to plan ahead with a greater degree of confidence."