That's all from the Business Live page for tonight. See you tomorrow from 06:00.
More Facebook testimony coverage can be found on the BBC World Live page.
Mark Zuckerberg says he will get back to Cantwell about whether Facebook employees worked with Cambridge Analytica.
New York Times political reporter Nick Confessore says he has an answer:
The committee chairman offers to take a quick break, but Zuckerberg, who has been drinking a lot of water during this hearing, said he can keep going.
"We can do a few more," he suggests as the testimony passes its second hour.
"Maybe, 15 minutes. Does that work?" he said to laughter in the room.
The senators seem happy to keep the question and answer session going.
Mr Zuckerberg was asked by Senator Dick Durbin: "Mr Zuckerberg, would you be comfortable sharing with us the name of the hotel you stayed in last night?" After a pause, and some laughter from himself and the room, Mr Zuckerberg said: "No."
"If you messaged anyone this week would you share with us the names of the people you have messaged?" Sen Durbin responded. "Senator, no, I would probably not choose to do that publicly here," Mr Zuckerberg said.
Mr Durbin said: "I think that may be what this is all about: your right to privacy, the limits of your right to privacy, and how much you give away, in modern America, in the name of connecting people around the world."
Away from the Facebook hearing for a moment... Wall Street stocks finished solidly higher amid easing of US-China trade tensions.
At the closing bell, the tech-rich Nasdaq was up 2.1% at 7,093.3 points, as Facebook jumped 4.5%. The Dow Jones added 1.8% to end the day at 24,405.3, while the broad-based S&P 500 advanced 1.7% to 2,656.7.
Senator Lindsey Graham starts by asking who Facebook's biggest competitor is.
"Senator we have a lot of competitors," Zuckerberg begins.
"Who's your biggest?" Graham interrupts.
"Do you want just one? I don't think I can give one. Can I name a bunch?" he responds.
Graham says: "Let me put it this way: If I buy a Ford and I don't like it I can buy a Chevy.
"If I'm upset with Facebook, what's the equivalent product that I can go sign up for?"
"Is there an alternative to Facebook in the private sector," he asks.
When Zuckerberg demurs, Graham interject: "You don't think you have a monopoly?"
"It certainly doesn't feel like that to me," Zuckerberg responds, noting that many Americans use eight social media platforms.
There's a ripple of laughter in the room.
Facebook's shares are on track to close at their highest level since 21 March. With a few minutes of trading left, the stock is up 4.7%.
The Facebook founder and CEO, Mark Zuckerberg, answered questions from US lawmakers about the hacking scandal.
Is Zuck referencing a future paid version of Facebook?
Facebook shares are climbing very rapidly as the senatorial hearing continues, now up more than 4.5%.
Several Twitter users are having a laugh at the technical questions about social media being asked by the mainly elderly senators.
This classic 2012 Twitter post from Senate Judiciary Committee Chairman Chuck Grassley has also been resurfacing.
"You can turn off third-party information," Zuckerberg says, when asked about how to stop seeing ads for a product that a user is not interested in.
"You consider my personal identifiable data the company's data, not my data, is that it?" asks Senator Nelson.
"No, senator," Zuckerberg responds, before taking a drink of water.
"We have made a lot of mistakes in running the company. I think it's pretty much impossible to start a company in your dorm room and then grow it to be the scale that we’re at now without making some mistakes.
"And because our service is about helping people connect and information those mistakes have been different."
"We did take action," Zuckerberg insists, "we took down the app and we demanded that both the app developer and Cambridge Analytica delete and stop using any data that they had. They told us that they did this. In retrospect it was clearly a mistake to believe them and we should have followed up and did a full audit then. And that is not a mistake that we will make."
"I believe its important to tell people how their information is going to be used," Zuckerberg says.
"Every single time" a user shares information, they are asked what community (friends, family, etc) they want to share that with, he notes.
"Long privacy policies are very confusing", he says, adding that the longer the terms of agreement become, the fewer people will agree to use the service.
"I believe it's important to tell people exactly how the information that they share on Facebook is going to be used," Zuckerberg tells Senator Grassley.
Facebook shares are climbing rapidly as Mark Zuckerberg gives his opening remarks to Congress and takes the first questions from senators.
Shares in the social media giant are more than 3.5% higher.
Facebook has confirmed a small number of Facebook users involved in the Cambridge Analytica breach gave access to their Facebook private messages.
About 1,500 users explicitly gave the app access to their inbox, but users who exchanged messages with those 1,500 would also be affected.
Carole Cadwalladr - the Observer journalist whose investigation helped plunge Facebook into the current crisis - was among the first to pick up on the implication.
Read more about who and what was affected.
This is "not the first time that Facebook has mishandled" data, notes Democratic Senator Bill Nelson, who adds that a third party "lied" to consumers and Facebook.
"Why didn't Facebok notify 87 million users that their personal information had been taken?" he asks, adding that the data was used for "unauthorised political purposes".
"I think you're genuine. I got that sense conversing with you" yesterday, the senator adds.
Judiciary committee chairman Chuck Grassley, a Republican, says: "In fact, President Obama's campaign developed an app utilising the same Facebook feature as Cambridge Analytica to capture the information of not just the app's users, but also millions of their friends."
"The effectiveness of these social media tactics can be debated.
"But their use of the past years across the political spectrum and their increased significance can not be ignored."
We're streaming Mark Zuckerberg's testimony in front of Congress on - yes, you guessed it, Facebook Live and sharing related news.
Zuckerberg sips water and looks straight ahead as the fourth senator finishes his remarks.
BBC technology correspondent Dave Lee has followed Mark Zuckerberg's apology tour from Silicon Valley to Washington.
Watch his Twitter account as he speaks to some of the lawmakers who are expected to grill Zuckerberg today.
"Never have we had such unfiltered access to a man who is typically wrapped in cotton wool by his PR team and deputies," says Lee in his preview piece.
Air France has raised its pay offer to unions in a bid to end strikes that have already cost the airline 170m euros (£150m).
The carrier, which is part of Air France-KLM, doubled the 1% pay increase previously offered to unions and proposed talks on a deal for the 2019-21 period in reponse to their demands for a 6% wage hike.
New York Times
McDonald's plans to open 200 restaurants in the Nordic region over the next 10 years and begin home deliveries this year, as it tries to win back fast food customers.
The moves are part of a drive to regain market share from rivals including Taco Bell and Dunkin' Donuts.
McDonald's has around 150 million customers a year in Denmark, Sweden, Norway and Finland, which it serves about 430 restaurants in the region.
Starting in May, the fast food chain will begin home delivery in Sweden and Finland, followed by Denmark and Norway in the second half of the year.
McDonald's in the Nordics operates under a development licence owned by UK investor Guy Hands, who bought the rights to its Nordic operations in January 2017.
Norway's $1trn sovereign wealth fund, the world's largest, should not be given permission to invest in unlisted companies, the country's finance ministry has said in recommendations to parliament, rejecting the fund's own advice.
The fund invests Norway's oil and gas revenues into stocks, bonds and property abroad, and is one of the world's biggest shareholders with stakes totalling 1.4% of all listed companies.
"Unlisted equity investments would challenge the management model based on transparency, low management costs, and a limited degree of active management," the finance ministry wrote in its annual white paper on the fund to parliament.