The pool of master limited partnerships with an investment grade rating is pretty small. In fact, only 16 of them have been rated BBB- or higher by Standard and Poor's. That means there are plenty of MLPs like Northern Tier Energy (NYSE: NTI ) , Linn Energy (NASDAQOTH: LINEQ ) , or Alliance Resource Partners (NASDAQ: ARLP ) that are out of luck. In this video, Fool.com contributor Aimee Duffy looks at the MLP space and explains why the aforementioned MLPs may never see an investment grade rating and what that means for the investors who hold them.
3 stocks for a rich retirement
The best investing approach is to choose great companies and stick with them for the long term. The Motley Fool's free report "3 Stocks That Will Help You Retire Rich" names stocks that could help you build long-term wealth and retire well, along with some winning wealth-building strategies that every investor should be aware of. Click here now to keep reading.