Stocks erase gains as bears emerge; Oil up for the week

Stocks can't hang on to gains as the bears emerge on the final day of the week. Is this a worrying sign of things to come? Yahoo Finance Editor-in-Chief Andy Serwer, Bobbi Rebell, and Joe Fahmy of Zor Capital break down all the big topics this week including Apple vs the FBI, Donald Trump's big week, and Warren Buffett upcoming letter to Berkshire shareholders.