6. UNSECURED LINE OF CREDIT AND TERM NOTES

The Company’s unsecured amended credit agreement includes a revolving credit facility with a limit of $500 million with a maturity date of March 10, 2023, and initially included a term note in the principal amount of $100 million with a maturity date of June 4, 2020 which has since been repaid. Such credit agreement provides for interest on the revolving credit facility at a variable annual rate equal to LIBOR plus a margin based on the Company’s credit rating (at June 30, 2021 the margin is 0.95%), interest on any term notes at a variable annual rate equal to LIBOR plus a margin based on the Company’s credit rating (at June 30, 2021 the margin is 1.00%), and requires an annual facility fee on the revolving credit facility which varies based upon the Company’s credit rating (at June 30, 2021 the facility fee is 0.15%). The interest rate on the Company’s revolving credit facility at June 30, 2021 was approximately 1.04% (1.09% at December 31, 2020) and the interest rate on any term notes at June 30, 2021 was approximately 1.09% (1.14% at December 31, 2020). At June 30, 2021 there was $359.9 million available on the unsecured line of credit. The Company has the option under this credit facility to increase the total aggregate borrowing capacity of the facilities to $900 million.

On September 23, 2020, the Operating Partnership issued $400 million in aggregate principal amount of 2.200% unsecured senior notes due October 15, 2030 (the “2030 Senior Notes”). The 2030 Senior Notes were issued at 0.476% discount to par value. Interest on the 2030 Senior Notes is payable semi-annually in arrears on each April 15 and October 15. Proceeds received upon issuance, net of discount to par of $1.9 million and underwriting and other offering expenses of $3.5 million, totaled $394.6 million.

On June 3, 2019, the Operating Partnership issued $350 million in aggregate principal amount of 4.000% unsecured senior notes due June 15, 2029 (the “2029 Senior Notes”). The 2029 Senior Notes were issued at a 0.524% discount to par value. Interest on the 2029 Senior Notes is payable semi-annually in arrears on each June 15 and December 15. Proceeds received upon issuance, net of discount to par of $1.8 million and underwriting discount and other offering expenses of $3.1 million, totaled $345.1 million.

On December 7, 2017, the Operating Partnership issued $450 million in aggregate principal amount of 3.875% unsecured senior notes due December 15, 2027 (the “2027 Senior Notes”). The 2027 Senior Notes were issued at a 0.477% discount to par value. Interest on the 2027 Senior Notes is payable semi-annually in arrears on each June 15 and December 15. Proceeds received upon issuance, net of discount to par of $2.1 million and underwriting discount and other offering expenses of $4.0 million, totaled $443.9 million.

On June 20, 2016, the Operating Partnership issued $600 million in aggregate principal amount of 3.50% unsecured senior notes due July 1, 2026 (the “2026 Senior Notes”). The 2026 Senior Notes were issued at a 0.553% discount to par value. Interest on the 2026 Senior Notes is payable semi-annually in arrears on each January 1 and July 1. Proceeds received upon issuance, net of discount to par of $3.3 million and underwriting discount and other offering expenses of $5.5 million, totaled $591.2 million.

The 2030 Senior Notes, the 2029 Senior Notes, the 2027 Senior Notes and the 2026 Senior Notes are all fully and unconditionally guaranteed by the Parent Company. The indenture under which the 2030 Senior Notes, the 2029 Senior Notes, the 2027 Senior Notes and the 2026 Senior Notes were issued restricts the ability of the Company and its subsidiaries to incur debt unless the Company and its consolidated subsidiaries comply with a leverage ratio not to exceed 60% and an interest coverage ratio of more than 1.5:1 on all outstanding debt, after giving effect to the incurrence of the debt. The indenture also restricts the ability of the Company and its subsidiaries to incur secured debt unless the Company and its consolidated subsidiaries comply with a secured debt leverage ratio not to exceed 40% after giving effect to the incurrence of the debt. The indenture also contains other financial and customary covenants, including a covenant not to own unencumbered assets with a value less than 150% of the unsecured indebtedness of the Company and its consolidated subsidiaries. At June 30, 2021, the Company was in compliance with such covenants.

On July 21, 2016, the Company entered into a $200 million term note maturing July 21, 2028 bearing interest at a fixed rate of 3.67%.

On April 8, 2014, the Company entered into a $175 million term note maturing April 8, 2024 bearing interest at a fixed rate of 4.533%. The interest rate on the term note increases to 6.283% if the Company is not rated by at least one rating agency or if the Company’s credit rating is downgraded.

The line of credit and term notes require the Company to meet certain financial covenants, measured on a quarterly basis, including prescribed leverage, fixed charge coverage, minimum net worth, limitations on additional indebtedness and limitations on dividend payouts. At June 30, 2021, the Company was in compliance with such covenants.

We believe that if operating results remain consistent with historical levels and levels of other debt and liabilities remain consistent with amounts outstanding at June 30, 2021, the entire availability on the line of credit could be drawn without violating our debt covenants.

The Company’s fixed rate term notes contain a provision that allows for the noteholders to call the debt upon a change of control of the Company at an amount that includes a make whole premium based on rates in effect on the date of the change of control.

Deferred debt issuance costs and the discount on the outstanding term notes are both presented as reductions of term notes in the accompanying consolidated balance sheets at June 30, 2021 and December 31, 2020. Amortization expense related to deferred debt issuance costs was $0.6 million for each of the three months ended June 30, 2021 and 2020 and $1.2 million for each of the six months ended June 30, 2021 and 2020, and is included in interest expense in the consolidated statements of operations.