Prospectus excerpt:  We are offering 1,000,000 shares of our 6.75% Series D Preferred Stock, or the “Series D Preferred Stock.” At any time on or after November 29, 2026, we may, at our sole option, redeem the outstanding shares of the Series D Preferred Stock at a redemption price of $25 per share, or the “Liquidation Preference,” plus accumulated but unpaid dividends, if any, to, but excluding, the Redemption Date (as defined below). In addition, if we fail to maintain asset coverage of at least 200%, we will be required to redeem the number of shares of our preferred stock (which at our discretion may include any number or portion of the Series D Preferred Stock) that, when combined with any debt securities redeemed for failure to maintain the asset coverage required by the indenture governing such securities, (1) results in us having asset coverage of at least 200%, or (2) if fewer, the maximum number of shares of preferred stock that can be redeemed out of funds legally available for such redemption. We intend to pay monthly dividends on the Series D Preferred Stock at an annual rate of 6.75% of the Liquidation Preference, or $1.6875 per share per year, beginning on December 31, 2021. The Series D Preferred Stock has no maturity date and will remain outstanding indefinitely unless redeemed by us. The Series D Preferred Stock will rank senior in right of payment to our common stock, will rank equally in right of payment with any shares of preferred stock (including our 7.75% Series B Term Preferred Stock due 2026 (the “Series B Term Preferred Stock”) and 6.50% Series C Term Preferred Stock due 2031 (the “Series C Term Preferred Stock”)) we have issued or may issue in the future and will be subordinated in right of payment to our existing and future senior indebtedness (including our 6.75% notes due 2027 (the “2027 Notes”), 6.6875% notes due 2028 (the “2028 Notes”) and 6.75% notes due 2031 (the “2031 Notes”)). Each holder of the Series D Preferred Stock will be entitled to one vote on each matter submitted to a vote of our stockholders, and the holders of all of our outstanding preferred stock and common stock will generally vote together as a single class. The holders of shares of the Series D Preferred Stock (together with the holders of our Series B Term Preferred Stock, Series C Term Preferred Stock and any additional series of preferred stock we may issue in the future) are entitled as a class to elect two of our directors and, if dividends on any outstanding shares of our preferred stock are in arrears by two years or more, to elect a majority of our directors.