Theresa May will use a speech to business leaders in Davos on Thursday to urge shareholders to pressure social media giants such as Twitter and Facebook to do more to tackle terrorism.
May flew to the Swiss ski resort for the World Economic Forum on Wednesday after prime minister's questions in the House of Commons.
She will call for more action from tech companies to identify and take down extremist content and say investors have a responsibility to pressure them to clean up their act.
"Investors can make a big difference here by ensuring trust and safety issues are being properly considered. And I urge them to do so," she will say, citing a recent case in which Facebook and Twitter shareholders called for the platforms to take tougher action.