Since 1980, pensions plans have been phased out in favor of 401(k) plans. They now represent nearly one-fifth of the U.S. retirement market. So how did 401(k) plans become such a popular form of retirement savings and how should they be used? Watch the video to find out. » Subscribe to CNBC: https://cnb.cx/SubscribeCNBC » Subscribe to CNBC TV: https://cnb.cx/SubscribeCNBCtelevision » Subscribe to CNBC Classic: https://cnb.cx/SubscribeCNBCclassic About CNBC: From 'Wall Street' to 'Main Street' to award winning original documentaries and Reality TV series, CNBC has you covered. Experience special sneak peeks of your favorite shows, exclusive video and more. Connect with CNBC News Online Get the latest news: https://www.cnbc.com/ Follow CNBC on LinkedIn: https://cnb.cx/LinkedInCNBC Follow CNBC News on Facebook: https://cnb.cx/LikeCNBC Follow CNBC News on Twitter: https://cnb.cx/FollowCNBC Follow CNBC News on Instagram: https://cnb.cx/InstagramCNBC Subscribe to CNBC PRO: https://cnb.cx/2NLi9AN #CNBC How 401(k) Plans Work And Why They Killed Pensions