payments made to our former CEO for termination of services as CEO and his service as Executive Chairman in the prior period.
Income Tax Expense
Our effective tax rate for the six months ended June 30, 2020 and 2019 was 21.9% and 21.8%, respectively. The increase in the effective tax rate in the six months ended June 30, 2020 compared to the same period in 2019 was primarily due to the tax effect of share-based compensation.
Our income tax expense was $6.7 million and $6.2 million for the periods ended June 30, 2020 and 2019, respectively. The increase is due to the increase in income before income taxes compared to the same period in 2019.
On March 27, 2020, the President of the United States signed into law the Coronavirus Aid, Relief, and Economic Security Act (the “CARES Act”). The CARES Act, among other things, includes certain income tax provisions for individuals and corporations; however, these benefits do not impact the Company’s current tax provision.
Adjusted Operating Income
Adjusted operating income was $24.9 million for the six months ended June 30, 2020, a decrease of $3.0 million, or 10.7% from the adjusted operating income of $27.9 million for the six months ended June 30, 2019.
Adjusted Operating Return on Equity
Our adjusted operating return on equity was 8.8% for the six months ended June 30, 2020, a decrease of 4.3% percentage points from 13.1% for the six months ended June 30, 2019 primarily due to the increase in average book value following our raise of primary equity during our initial public offering in 2019 combined with the decrease in adjusted operating income.
Liquidity and Capital Resources
Sources and Uses of Funds
We are organized as a holding company with our operations primarily conducted by our wholly owned insurance subsidiaries, New York Marine and Gotham, which are domiciled in New York, and Southwest Marine, which is domiciled in Arizona. Accordingly, the holding company may receive cash through (i) loans from banks, (ii) draws on a revolving loan agreement, (iii) issuance of equity and debt securities, (iv) corporate service fees from our operating subsidiaries, (v) payments from our subsidiaries pursuant to our consolidated tax allocation agreement and other transactions and (vi) subject to certain limitations discussed below, dividends from our insurance subsidiaries. We also may use the proceeds from these sources to contribute funds to the insurance subsidiaries in order to support premium growth, reduce our reliance on reinsurance, and pay dividends and taxes and for other business purposes.
We receive corporate service fees from the operating subsidiaries to reimburse us for most of the operating expenses that we incur. Reimbursement of expenses through corporate service fees is based on the actual costs that we expect to incur with no mark-up above our expected costs.
Our outstanding $140.0 million aggregate principal amount of 7.5% Senior Unsecured Notes and $25.0 million aggregate principal amount of 6.5% Senior Notes (collectively, the “Notes”) mature in November 2020.
Management believes that the Company has sufficient liquidity available to meet its operating cash needs and obligations and committed capital expenditures for the next 12 months.
Credit Agreement
On June 12, 2020 (the “Effective Date”), we entered into a credit agreement (the “Credit Agreement”) with certain lenders and Truist Bank, N.A., as administrative agent (“Truist”), providing for a $165.0 million delayed draw term loan facility (the “Term Loan Facility”). Borrowings under the Term Loan Facility will be used to refinance the Notes at