| | | |
AAA | | 45.9 | % |
AA | | 17.9 | % |
A | | 20.4 | % |
BBB | | 9.3 | % |
BB | | 3.2 | % |
B | | 2.4 | % |
CCC | | 0.3 | % |
NR | | 0.6 | % |
Total | | 100.0 | % |
As of June 30, 2020, the duration of the fixed income portfolio was 4.6 years. Our fixed income portfolio remained well diversified, with 1,288 individual issues.
Our investment portfolio has limited exposure to structured asset-backed securities. As of June 30, 2020, we had $137.9 million in ABS which are pools of assets collateralized by cash flows from several types of loans, including home equity, credit cards, autos and structured bank loans in the form of collateralized loan obligations (CLOs).
As of June 30, 2020, we had $80.6 million in commercial mortgage backed securities and $409.2 million in mortgage backed securities backed by government sponsored enterprises (GSEs - Freddie Mac, Fannie Mae and Ginnie Mae). Excluding the GSE backed MBS, our exposure to ABS and CMBS was 8.2 percent of our investment portfolio at quarter end.
We had $765.1 million in corporate fixed income securities as of June 30, 2020, which includes $98.2 million invested in a high yield credit strategy. This high-yield portfolio consists of floating rate bank loans and bonds that are below investment grade in credit quality and offer incremental yield over our core fixed income portfolio.
We also maintain an allocation to municipal fixed income securities. As of June 30, 2020, we had $455.7 million in municipal securities. The municipal portfolio includes approximately 73 percent tax-exempt securities and 27 percent taxable securities. Approximately 86 percent of our municipal bond portfolio maintains an ‘AA’ or better rating, while 99 percent of the municipal bond portfolio is rated ‘A’ or better.
Our equity portfolio had a fair value of $422.2 million as of June 30, 2020 and is also a source of liquidity. The securities within the equity portfolio remain primarily invested in large-cap issues with a focus on dividend income. In the equity portfolio, the strategy remains one of value investing, with security selection taking precedence over market timing.
As of June 30, 2020, our equity portfolio had a dividend yield of 2.1 percent, compared to 1.9 percent for the S&P 500 index. Because of the corporate dividend-received-deduction applicable to our dividend income, we pay an effective tax rate of 13.1 percent on dividends, compared to 21.0 percent on taxable interest and 5.3 percent on municipal bond interest income. The equity portfolio is managed in a diversified and granular manner, with 221 individual securities and three ETF positions. No single stock exposure is greater than 2 percent of the equity portfolio.
We had $63.4 million of other invested assets at June 30, 2020, including investments in low income housing tax credit partnerships, membership in the FHLBC, investments in private funds and investments in restricted stock. As of June 30, 2020, $14.6 million of investments were pledged as collateral with the FHLBC to ensure timely access to the secured lending facility that ownership of FHLBC stock provides. As of and during the six-month period ending June 30, 2020, there were no outstanding borrowings with the FHLBC.
Our investment portfolio does not have any exposure to derivatives.
Our capital structure is comprised of equity and debt outstanding. As of June 30, 2020, our capital structure consisted of $149.4 million in 10-year maturity senior notes maturing in 2023 (debt) and $1.1 billion of shareholders’ equity. Debt outstanding comprised 12.4 percent of total capital as of June 30, 2020. Interest and fees on debt obligations totaled $3.8 million during the first six months of 2020, compared to $3.7 million during the same period in 2019. We have incurred interest expense on debt at an average annual interest rate of 4.91 percent for the three-month periods ended June 30, 2020 and 2019.
We paid a regular quarterly cash dividend of $0.24 per share on June 19, 2020, a $0.01 increase over the prior quarter. We have increased dividends in each of the last 45 years.