A Kiplinger.com article discussed a bunch of high-dividend-paying funds labeled as oil and gas royalty trusts. Same as REIT, the income of those trusts are not taxed at company level and most income is passed out to investors as dividends.
I'm interested in learning this new category because I spent some time in REIT before and my investment in a mortgage-backed REIT FBR has brought an ROI of 31% (and ARR or 137%).
The article cautioned that some funds may be overvalued at the moment, albeit with 10%+ dividend yield right now. Also, those funds are sensitive to oil price change. I side with the article on the valuation. In addition, as I have no more knowledge in commodities like oil than any ordinary folks, I may need to spend more time to understand the underlying businesses of the funds. I'll put some of the mentioned funds like PTF and ERF in my watch list for now and research them later.