In a yield-starved environment, mREITs sporting double-digit dividends have caught the attention of many investors. One company that has grown extremely fast during the Fed's QE programs is American Capital Agency (AGNC).

The mREIT's asset balance has ballooned during the past several years, and investors saw huge total returns during that time. However, the mortgage-backed securities on its books lost value in the most recent quarter. Is this a concern?

In this video, Motley Fool financial analyst David Hanson reminds investors of the relationship between the dividend and the balance sheet and why investors should be asking themselves a few questions.