One very popular asset class among conservative income investors is preferred stock. This makes sense, as preferred stock is generally considered to be safer than common equity due to the fact that it sits higher up in a company's capital stack. In addition, preferred stock usually has a higher dividend yield than the common stock of the same company. However, it can be rather expensive and something of a hassle to construct a diversified portfolio of these assets. For this reason, investors may want to use funds in order to get exposure to preferred securities.