Sofia / Bloomberg The Bulgarian government started a tender for a 35-year concession to operate Sofia Airport, the country’s biggest, demanding at least 660 million lev ($382 million) in initial payment. The concessionaire will be required to invest at least 307 million lev in the airport, which includes building a new terminal with an annual capacity of 3 million …

  MENLO PARK / Tribune News Service With a microphone floating in zero gravity, three astronauts aboard the International Space Station chatted with Facebook CEO Mark Zuckerberg via live video about life in space. The social media company has been ramping up its efforts in live video this year, taking on Twitter-owned Periscope. The recent event was the first time …

  Reuters Gulf Arab investors, some of the biggest buyers of British real estate, are holding back from new deals because they fear a property price slump if Britain leaves the European Union, according to legal and investment sources. Sovereign and private investors from Qatar, Saudi Arabia, Kuwait and the United Arab Emirates have been prolific buyers of British assets …