Hillary Clinton's tax plan would impose a 65% tax on the largest estates and make it harder for wealthy people to pass appreciated assets to their heirs without paying taxes. In all, the Democrat presidential candidates plan would increase taxes by $1.5 trillion over the next decade. She says it would generate $260 billion over the next decade. Facebook ( ) was found to have overestimated a key video metric for two years. The Wall Street Journal says the tech giant overestimated the video view time by 80% in some cases. Big ad buyers and marketers are upset. Facebook says it's corrected the error. Crude oil prices are slipping after two strong days. Caution is taking over ahead of a gathering of OPEC ministers next week in Algeria. There are also looming supply additions from Nigeria and Libya.