Global wealth inequality widened last year as billionaires increased their fortunes by $2.5 billion per day, anti-poverty campaigner Oxfam said in a new report. While the poorest half of humanity saw their wealth dwindle by 11%, billionaires’ riches increased by 12%. The mega-wealthy have also become a more concentrated bunch. Last year, the top 26 wealthiest people owned $1.4 trillion, or as much as the 3.8 billion poorest people.