These two high-yielding monthly dividend stocks go head-to-head.AGNC Investment (AGNC 0.76%) offers one of the highest dividend yields at nearly 15%. That's over 10 times higher than the S&P 500's current near-historic low yield of less than 1.2% and more than twice the yield of Healthpeak Properties (DOC), around 6.5%. However, that higher yield alone doesn't mean it's a better high-dividend REIT. Let's take a closer look at these big-time dividend stocks. A monster monthly income streamAGNC Investment hol ...