This ETF offers investors exposure to preferred stock, an interesting segment of the capital markets that most investors do not have a lot of exposure to. Preferred stock holders have a 'preferred' position on assets compared to other common shareholders should there be a liquidity event in the company. However, these shareholders generally do not have voting rights in exchange for this premium position. Preferred stock also generally pay out solid dividend yields but then also do not participate as much in equity appreciation as their common share counterparts. Due to this preferred stock could be appropriate for those seeking to boost yields in a portfolio or for those looking for less risky forms of equity exposure that are relatively absent from broad portfolios of stocks. PSK is reasonably diversified by both sector and in terms of total number of holdings; the fund has just over 160 securities and is heavily weighted towards the financial industry although other sectors do comprise nearly 20% of the fund as well. As a result, this fund should be considered part of the financial holding of a portfolio and only used in small amounts to boost yields. If used properly, PSK could be a powerful tool for investors, just be careful and make sure to not overinvest in the sector.