*The ratio of total assets of the Fund, less all liabilities that are not outstanding borrowings or outstanding preferreds, at par, to the sum of the Fund’s outstanding borrowings and outstanding preferreds, at par.

**The annualized ratio of the sum of leverage costs to the average leverage amount for a given time period.

Fund fees and expenses are presented as a percentage of both common shareholder capital and total fund investment capital. The first column portrays the costs directly and indirectly borne by common shareholders. The second column portrays the costs borne by the Fund on its total investment capital, which includes common assets as well as assets attributable to the Fund's issuance of senior securities (e.g. preferred shares and debt). This column enables a common shareholder to better understand how fund expenses impact portfolio investment returns. Interest expenses from leverage represent costs associated with the Fund's financing activities, which are distinct from the costs associated with the Fund's underlying core operations. Certain leveraging instruments including repurchase agreements (repos) are sometimes more efficient forms of leverage, but when used, the costs are difficult to accurately disaggregate and are not shown here.

Other Expenses and Total Expenses do not include interest expenses arising from the application of SFAS No. 140 to certain inverse floating rate securities (if any) held by the Fund. Interest expense arises because accounting rules require the Fund to treat interest paid by trusts issuing certain inverse floating rate instruments held by the Fund as having been paid (indirectly) by the Fund. Because the Fund also recognizes a corresponding amount of additional income earned (also indirectly), the Fund's net asset value per share, net investment income and total return have not been affected by this accounting treatment. See the Fund's Annual Report for information on the Fund's inverse floating rate investments and recognized interest expense.​

Expense ratios are calculated using the prior 12 months of expense data as of the previous month-end. Annualized leverage financing expense is included if the Fund was leveraged as of the previous month end.

For the percentage of the portfolio in debt, preferred and other hybrid securities, including CoCos (if any). Percentages reflect the percentage of the Fund's investment exposure callable in the timeframe relative to the “as of” date shown. The "Next 12 months" figure (if shown) includes investments that are currently callable, as well as callable in the next 12 months. Securities subject to call may not be called.

Ratings shown are the lowest rating given by one of the following national rating agencies: S&P, Moody's or Fitch. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC/CC/C and D are below-investment grade ratings. U.S. government securities, if owned by the Fund, are included in the U.S. Treasury/Agency category (included only if applicable). Holdings designated NR are not rated by these national rating agencies.