When investors read about real estate investment trusts, they often assume that those companies invest in residential or commercial properties, such as office buildings, medical clinics, or shopping centers. However, there's another niche within the group of commercial properties that's just as interesting but doesn't seem to get the same kind of attention.

The niche I'm talking about is storage facilities. And Iron Mountain Incorporated
(NYSE:IRM) is one of the first companies that comes to mind in this often overlooked segment of real estate investing.
Business profile
The Boston-based company was founded in 1951 by Herman Knaust and has since evolved into one of the leading storage and information management services companies in the United States, serving approximately 155,000 customers in 36 countries. This year, the company converted into a REIT, a classification that requires the company to pay out at least 90% of its taxable income to avoid corporate taxation.
Solid revenue trend
Storage and information management services are an attractive niche that has seen solid rental growth over the years. Most companies in developed countries are required by law to secure their records and business correspondence, which in turn leads to both high demand for storage facilities and a non-cyclical revenue trend for Iron Mountain.

Source: Iron Mountain third-quarter earnings presentation.

Though the North American market and Iron Mountain's core segment of records management are the dominant revenue drivers for the company, it's good to see that the REIT has ventured into other service lines as well, such as data protection and information destruction, to diversify its revenue base.
At the end of Iron Mountain's third quarter, the company achieved more than 70% of its revenues in North America, and approximately 68% of its total revenues from records management, giving Iron Mountain plenty of room to expand its complimentary service offerings and grow its revenues in underserved markets.

Source: Iron Mountain third-quarter earnings presentation.

Formidable size, resilient business model
If anything puts a real estate-focused business on the success track, it is size and scale. A large, multinational operations footprint allows a REIT to navigate local real estate downturns and diversify its revenue base.

Iron Mountain certainly is not a small player by any means, thanks to its history of acquisitions: Its real estate portfolio now consists of more than 1,000 properties with 67 million square feet. Since Iron Mountain, according to its own statement, serves "more than 95% of Fortune 1000 companies" and operates in more than 30 countries, the REIT's cash flows and dividends are standing on solid ground.

Source: Iron Mountain investor presentation, November 2014.

Dividend stream
The conversion to a REIT makes the company attractive for income investors who are looking for stable and/or growing dividends that are backed by recurring cash flows originating from Iron Mountain's storage property portfolio.

Dividend safety is an issue that's highly relevant to investors, but it shouldn't be a major concern for Iron Mountain: Companies need to store their records in good times and bad, which lends a lot of stability to Iron Mountain's revenue and dividend stream.
Iron Mountain currently exhibits a dividend yield of 5.04% (per data from S&P Capital IQ). But if the REIT can continue to benefit from rising rental revenues, as it did in the past, investors could see even higher yields and dividends down the road.
Investors don't always have to gravitate toward the traditional residential real estate market when looking for real estate-derived cash flows and dividend income. Storage providers with diversified revenue bases and an international footprint are just as attractive.
Iron Mountain's conversion to a REIT was certainly a good move for the company to pamper investors with a decent 5% dividend yield. Its fairly low-risk revenues add to Iron Mountain's attractiveness as an income play.