Marissa Mayer attends the eighth annual Breakthrough Prize awards in Mountain View, California, U.S., November 3, 2019. REUTERS/Kate Munsch 

Marissa Mayer attends the eighth annual Breakthrough Prize awards in Mountain View, California, U.S., November 3, 2019. REUTERS/Kate Munsch 

Equifax Interim CEO Paulino Barros (L), former Equifax CEO Richard Smith (C) and former Yahoo Chief Executive Marissa Mayer (R) testify before a Senate Commerce, Science and Transportation hearing on "Protecting Consumers in the Era of Major Data Breaches" on Capitol Hill in Washington, U.S., November 8, 2017. REUTERS/Kevin Lamarque 

Equifax Interim CEO Paulino Barros (L), former Equifax CEO Richard Smith (C) and former Yahoo Chief Executive Marissa Mayer (R) testify before a Senate Commerce, Science and Transportation hearing on "Protecting Consumers in the Era of Major Data Breaches" on Capitol Hill in Washington, U.S., November 8, 2017. REUTERS/Kevin Lamarque 

Equifax Interim CEO Paulino Barros (L), former Equifax CEO Richard Smith (C) and former Yahoo Chief Executive Marissa Mayer (R) testify before a Senate Commerce, Science and Transportation hearing on "Protecting Consumers in the Era of Major Data Breaches" on Capitol Hill in Washington, U.S., November 8, 2017. REUTERS/Kevin Lamarque 

Former Yahoo Chief Executive Marissa Mayer (R), former Equifax CEO Richard Smith (C) and Equifax Interim CEO Paulino Barros (L) testify before a Senate Commerce, Science and Transportation hearing on "Protecting Consumers in the Era of Major Data Breaches" on Capitol Hill in Washington, U.S., November 8, 2017. REUTERS/Kevin Lamarque 

Equifax Interim CEO Paulino Barros (L), former Equifax CEO Richard Smith (C) and former Yahoo Chief Executive Marissa Mayer (R) testify before a Senate Commerce, Science and Transportation hearing on "Protecting Consumers in the Era of Major Data Breaches" on Capitol Hill in Washington, U.S., November 8, 2017. REUTERS/Kevin Lamarque 

Equifax Interim CEO Paulino Barros (L), former Equifax CEO Richard Smith (C) and former Yahoo Chief Executive Marissa Mayer testify before a Senate Commerce, Science and Transportation hearing on "Protecting Consumers in the Era of Major Data Breaches" on Capitol Hill in Washington, U.S., November 8, 2017. REUTERS/Kevin Lamarque 

Equifax Interim CEO Paulino Barros (L), former Equifax CEO Richard Smith (C) and former Yahoo Chief Executive Marissa Mayer testify before a Senate Commerce, Science and Transportation hearing on "Protecting Consumers in the Era of Major Data Breaches" on Capitol Hill in Washington, U.S., November 8, 2017. REUTERS/Kevin Lamarque 

Equifax Interim CEO Paulino Barros (L), former Equifax CEO Richard Smith (C) and former Yahoo Chief Executive Marissa Mayer (R) testify before a Senate Commerce, Science and Transportation hearing on "Protecting Consumers in the Era of Major Data Breaches" on Capitol Hill in Washington, U.S., November 8, 2017. REUTERS/Kevin Lamarque 

Equifax Interim CEO Paulino Barros (L), former Equifax CEO Richard Smith (C) and former Yahoo Chief Executive Marissa Mayer testify before a Senate Commerce, Science and Transportation hearing on "Protecting Consumers in the Era of Major Data Breaches" on Capitol Hill in Washington, U.S., November 8, 2017. REUTERS/Kevin Lamarque 

Equifax Interim CEO Paulino Barros (L), former Equifax CEO Richard Smith (C) and former Yahoo Chief Executive Marissa Mayer testify before a Senate Commerce, Science and Transportation hearing on "Protecting Consumers in the Era of Major Data Breaches" on Capitol Hill in Washington, U.S., November 8, 2017. REUTERS/Kevin Lamarque 

Former Yahoo Chief Executive Marissa Mayer waits to testify before a Senate Commerce, Science and Transportation hearing on "Protecting Consumers in the Era of Major Data Breaches" on Capitol Hill in Washington, U.S., November 8, 2017. REUTERS/Kevin Lamarque 

Marissa Mayer, President and CEO of Yahoo, participates in a panel discussion at the 2015 Fortune Global Forum in San Francisco, California, U.S. on November 3, 2015. REUTERS/Elijah Nouvelage 

Marissa Mayer, President and CEO of Yahoo, participates in a panel discussion at the 2015 Fortune Global Forum in San Francisco, California, U.S. November 3, 2015. REUTERS/Elijah Nouvelage/File Photo 

Marissa Mayer, President and CEO of Yahoo, participates in a panel discussion at the 2015 Fortune Global Forum in San Francisco, California November 3, 2015. REUTERS/Elijah Nouvelage 

Marissa Mayer, President and CEO of Yahoo, participates in a panel discussion at the 2015 Fortune Global Forum in San Francisco, California November 3, 2015. REUTERS/Elijah Nouvelage 

Marissa Mayer, President and CEO of Yahoo, participates in a panel discussion at the 2015 Fortune Global Forum in San Francisco, California November 3, 2015. REUTERS/Elijah Nouvelage 

Marissa Mayer, President and CEO of Yahoo, participates in a panel discussion at the 2015 Fortune Global Forum in San Francisco, California November 3, 2015. REUTERS/Elijah Nouvelage 

Marissa Mayer, President and CEO of Yahoo, participates in a panel discussion at the 2015 Fortune Global Forum in San Francisco, California November 3, 2015. REUTERS/Elijah Nouvelage 

Marissa Mayer, President and CEO of Yahoo, (R) participates in a panel discussion with Marc Benioff, CEO of Salesforce, (C) at the 2015 Fortune Global Forum in San Francisco, California November 3, 2015. REUTERS/Elijah Nouvelage 

Marissa Mayer, President and CEO of Yahoo, participates in a panel discussion at the 2015 Fortune Global Forum in San Francisco, California November 3, 2015. REUTERS/Elijah Nouvelage 

Marissa Mayer, President and CEO of Yahoo, participates in a panel discussion at the 2015 Fortune Global Forum in San Francisco, California November 3, 2015. REUTERS/Elijah Nouvelage 

Yahoo! CEO Marissa Mayer arrives at the Metropolitan Museum of Art Costume Institute Gala 2015 celebrating the opening of "China: Through the Looking Glass," in Manhattan, New York May 4, 2015. REUTERS/Lucas Jackson 

Marissa Ann Mayer, president and CEO of Yahoo!, arrives for the Metropolitan Museum of Art Costume Institute Gala 2015 celebrating the opening of "China: Through the Looking Glass," in Manhattan, New York May 4, 2015. REUTERS/Andrew Kelly 

Marissa Ann Mayer, president and CEO of Yahoo!, arrives for the Metropolitan Museum of Art Costume Institute Gala 2015 celebrating the opening of "China: Through the Looking Glass," in Manhattan, New York May 4, 2015. REUTERS/Andrew Kelly 

Yahoo CEO Marissa Mayer arrives at the Metropolitan Museum of Art Costume Institute Gala 2015 celebrating the opening of "China: Through the Looking Glass" in Manhattan, New York May 4, 2015. REUTERS/Lucas Jackson 

Yahoo CEO Marissa Mayer speaks before the session "In Tech We Trust" in the Swiss mountain resort of Davos January 22, 2015. More than 1,500 business leaders and 40 heads of state or government attend the Jan. 21-24 meeting of the World Economic Forum (WEF) to network and discuss big themes, from the price of oil to the future of the Internet. This year they are meeting in the midst of upheaval, with security forces on heightened alert after attacks in Paris, the European Central Bank considering a radical government bond-buying programme and the safe-haven Swiss franc rocketing. REUTERS/Ruben Sprich (SWITZERLAND - Tags: BUSINESS POLITICS)

Yahoo CEO Marissa Mayer smiles before the session "In Tech We Trust" in the Swiss mountain resort of Davos January 22, 2015. More than 1,500 business leaders and 40 heads of state or government attend the Jan. 21-24 meeting of the World Economic Forum (WEF) to network and discuss big themes, from the price of oil to the future of the Internet. This year they are meeting in the midst of upheaval, with security forces on heightened alert after attacks in Paris, the European Central Bank considering a radical government bond-buying programme and the safe-haven Swiss franc rocketing. REUTERS/Ruben Sprich (SWITZERLAND - Tags: BUSINESS POLITICS)

Yahoo CEO Marissa Mayer gestures before the session "In Tech We Trust" in the Swiss mountain resort of Davos January 22, 2015. More than 1,500 business leaders and 40 heads of state or government attend the Jan. 21-24 meeting of the World Economic Forum (WEF) to network and discuss big themes, from the price of oil to the future of the Internet. This year they are meeting in the midst of upheaval, with security forces on heightened alert after attacks in Paris, the European Central Bank considering a radical government bond-buying programme and the safe-haven Swiss franc rocketing. REUTERS/Ruben Sprich (SWITZERLAND - Tags: BUSINESS POLITICS)

Yahoo CEO Marissa Mayer smiles before the session "In Tech We Trust" in the Swiss mountain resort of Davos January 22, 2015. More than 1,500 business leaders and 40 heads of state or government attend the Jan. 21-24 meeting of the World Economic Forum (WEF) to network and discuss big themes, from the price of oil to the future of the Internet. This year they are meeting in the midst of upheaval, with security forces on heightened alert after attacks in Paris, the European Central Bank considering a radical government bond-buying programme and the safe-haven Swiss franc rocketing. REUTERS/Ruben Sprich (SWITZERLAND - Tags: BUSINESS POLITICS)

Yahoo CEO Marissa Mayer smiles before the session "In Tech We Trust" in the Swiss mountain resort of Davos January 22, 2015. More than 1,500 business leaders and 40 heads of state or government attend the Jan. 21-24 meeting of the World Economic Forum (WEF) to network and discuss big themes, from the price of oil to the future of the Internet. This year they are meeting in the midst of upheaval, with security forces on heightened alert after attacks in Paris, the European Central Bank considering a radical government bond-buying programme and the safe-haven Swiss franc rocketing. REUTERS/Ruben Sprich (SWITZERLAND - Tags: BUSINESS POLITICS TPX IMAGES OF THE DAY)

Yahoo CEO Marissa Mayer gestures before the session "In Tech We Trust" in the Swiss mountain resort of Davos January 22, 2015. More than 1,500 business leaders and 40 heads of state or government attend the Jan. 21-24 meeting of the World Economic Forum (WEF) to network and discuss big themes, from the price of oil to the future of the Internet. This year they are meeting in the midst of upheaval, with security forces on heightened alert after attacks in Paris, the European Central Bank considering a radical government bond-buying programme and the safe-haven Swiss franc rocketing. REUTERS/Ruben Sprich (SWITZERLAND - Tags: BUSINESS POLITICS)

Yahoo CEO Marissa Mayer gestures before the session "In Tech We Trust" in the Swiss mountain resort of Davos January 22, 2015. More than 1,500 business leaders and 40 heads of state or government attend the Jan. 21-24 meeting of the World Economic Forum (WEF) to network and discuss big themes, from the price of oil to the future of the Internet. This year they are meeting in the midst of upheaval, with security forces on heightened alert after attacks in Paris, the European Central Bank considering a radical government bond-buying programme and the safe-haven Swiss franc rocketing. REUTERS/Ruben Sprich (SWITZERLAND - Tags: BUSINESS POLITICS)

Yahoo CEO Marissa Mayer smiles before the session "In Tech We Trust" in the Swiss mountain resort of Davos January 22, 2015. More than 1,500 business leaders and 40 heads of state or government attend the Jan. 21-24 meeting of the World Economic Forum (WEF) to network and discuss big themes, from the price of oil to the future of the Internet. This year they are meeting in the midst of upheaval, with security forces on heightened alert after attacks in Paris, the European Central Bank considering a radical government bond-buying programme and the safe-haven Swiss franc rocketing. REUTERS/Ruben Sprich (SWITZERLAND - Tags: BUSINESS POLITICS)

Yahoo CEO Marissa Mayer smiles before the session "In Tech We Trust" in the Swiss mountain resort of Davos January 22, 2015. More than 1,500 business leaders and 40 heads of state or government attend the Jan. 21-24 meeting of the World Economic Forum (WEF) to network and discuss big themes, from the price of oil to the future of the Internet. This year they are meeting in the midst of upheaval, with security forces on heightened alert after attacks in Paris, the European Central Bank considering a radical government bond-buying programme and the safe-haven Swiss franc rocketing. REUTERS/Ruben Sprich (SWITZERLAND - Tags: BUSINESS POLITICS)

Yahoo CEO Marissa Mayer speaks at a Salesforce event at the Commonwealth Club in San Francisco, California October 30, 2014. REUTERS/Robert Galbraith (UNITED STATES - Tags: BUSINESS) 

Salesforce CEO Marc Benioff and Yahoo CEO Marissa Mayer during a Salesforce event at the Commonwealth Club in San Francisco, California October 30, 2014. REUTERS/Robert Galbraith (UNITED STATES - Tags: BUSINESS) 

Salesforce CEO Marc Benioff and Yahoo CEO Marissa Mayer during a Salesforce event at the Commonwealth Club in San Francisco, California October 30, 2014. REUTERS/Robert Galbraith (UNITED STATES - Tags: BUSINESS) 

Salesforce CEO Marc Benioff and Yahoo CEO Marissa Mayer applaud during a Salesforce event at the Commonwealth Club in San Francisco, California October 30, 2014. REUTERS/Robert Galbraith (UNITED STATES - Tags: BUSINESS) 

U.S. President Barack Obama is introduced to speak by Yahoo CEO Marissa Mayer at a DNC fund raiser in San Jose, California May 8, 2014. REUTERS/Kevin Lamarque (UNITED STATES - Tags: POLITICS) 

Marissa Mayer, Chief Executive Officer of Yahoo, speaks during a session at the World Economic Forum (WEF) in Davos January 25, 2014. REUTERS/Denis Balibouse (SWITZERLAND - Tags: POLITICS BUSINESS SCIENCE TECHNOLOGY) 

Marissa Mayer, Chief Executive Officer of Yahoo speaks during a session at the World Economic Forum (WEF) in Davos January 25, 2014. REUTERS/Ruben Sprich (SWITZERLAND - Tags: POLITICS BUSINESS)

Marissa Mayer, Chief Executive Officer of Yahoo speaks during a session at the World Economic Forum (WEF) in Davos January 25, 2014. REUTERS/Denis Balibouse (SWITZERLAND - Tags: POLITICS BUSINESS)

Marissa Mayer, Chief Executive Officer of Yahoo attends a session at the World Economic Forum (WEF) in Davos January 25, 2014. REUTERS/Denis Balibouse (SWITZERLAND - Tags: POLITICS BUSINESS)

Marissa Mayer, Chief Executive Officer of Yahoo attends a session at the World Economic Forum (WEF) in Davos January 25, 2014. REUTERS/Denis Balibouse (SWITZERLAND - Tags: POLITICS BUSINESS)

Marissa Mayer, Chief Executive Officer of Yahoo, Co-Chair of the World Economic Forum Annual Meeting 2014, attends a session at the annual meeting of the World Economic Forum (WEF) in Davos January 24, 2014. REUTERS/Denis Balibouse (SWITZERLAND - Tags: POLITICS BUSINESS)

Marissa Mayer, Chief Executive Officer of Yahoo, Co-Chair of the World Economic Forum Annual Meeting 2014, attends a session at the annual meeting of the World Economic Forum (WEF) in Davos January 24, 2014. REUTERS/Denis Balibouse (SWITZERLAND - Tags: POLITICS BUSINESS)

Marissa Mayer, Chief Executive Officer of Yahoo and Co-Chair of the World Economic Forum Annual Meeting (WEF) 2014, speaks during a session at the annual WEF meeting in Davos January 22, 2014. REUTERS/Ruben Sprich (SWITZERLAND - Tags: POLITICS BUSINESS HEADSHOT)

Marissa Mayer, Chief Executive Officer of Yahoo and Co-Chair of the World Economic Forum Annual Meeting (WEF) 2014, smiles during a session at the annual WEF meeting in Davos January 22, 2014. REUTERS/Ruben Sprich (SWITZERLAND - Tags: POLITICS BUSINESS HEADSHOT)

Marissa Mayer, Chief Executive Officer of Yahoo and Co-Chair of the World Economic Forum Annual Meeting (WEF) 2014, smiles during a session at the annual WEF meeting in Davos January 22, 2014. REUTERS/Ruben Sprich (SWITZERLAND - Tags: POLITICS BUSINESS HEADSHOT)

Yahoo CEO Marissa Mayer delivers her keynote address at the annual Consumer Electronics Show (CES) in Las Vegas, Nevada January 7, 2014. REUTERS/Robert Galbraith (UNITED STATES - Tags: BUSINESS SCIENCE TECHNOLOGY ENTERTAINMENT) 

Yahoo CEO Marissa Mayer speaks during her keynote address at the annual Consumer Electronics Show (CES) in Las Vegas, Nevada January 7, 2014. REUTERS/Robert Galbraith (UNITED STATES - Tags: SCIENCE TECHNOLOGY BUSINESS) 

Yahoo CEO Marissa Mayer speaks during her keynote address at the annual Consumer Electronics Show (CES) in Las Vegas, Nevada January 7, 2014. REUTERS/Robert Galbraith (UNITED STATES - Tags: SCIENCE TECHNOLOGY BUSINESS) 

Yahoo CEO Marissa Mayer speaks during her keynote address at the annual Consumer Electronics Show (CES) in Las Vegas, Nevada January 7, 2014. REUTERS/Robert Galbraith (UNITED STATES - Tags: SCIENCE TECHNOLOGY BUSINESS) 

Yahoo CEO Marissa Mayer enters the stage to deliver her keynote address at the annual Consumer Electronics Show (CES) in Las Vegas, Nevada January 7, 2014. REUTERS/Robert Galbraith (UNITED STATES - Tags: SCIENCE TECHNOLOGY BUSINESS) 

Yahoo CEO Marissa Mayer speaks during her keynote address at the annual Consumer Electronics Show (CES) in Las Vegas, Nevada January 7, 2014. REUTERS/Robert Galbraith (UNITED STATES - Tags: SCIENCE TECHNOLOGY BUSINESS) 

Yahoo CEO Marissa Mayer speaks during her keynote address at the annual Consumer Electronics Show (CES) in Las Vegas, Nevada January 7, 2014. REUTERS/Robert Galbraith (UNITED STATES - Tags: SCIENCE TECHNOLOGY BUSINESS) 

Yahoo CEO Marissa Mayer (R) joins journalist Katie Couric on stage during Mayer's keynote speech at the annual Consumer Electronics Show (CES) in Las Vegas, Nevada January 7, 2014. Couric joins Yahoo as a global anchor. REUTERS/Robert Galbraith (UNITED STATES - Tags: SCIENCE TECHNOLOGY BUSINESS) 

Yahoo CEO Marissa Mayer (R) greets journalist Katie Couric on stage during Mayer's keynote speech at the annual Consumer Electronics Show (CES) in Las Vegas, Nevada January 7, 2014. Couric will join Yahoo as a global anchor. REUTERS/Robert Galbraith (UNITED STATES - Tags: BUSINESS)