new $600 million term loan B facility to institutional investors with a term expiring on March 13, 2025; (3) increase the capacity of our revolving credit facility from $1.05 billion to $1.35 billion and extend its term until March 13, 2023; (4) reduce our interest rate borrowing costs as follows: (a) the term loan B facility, at our election, Base Rate (as defined in the Credit Agreement) plus 0.75% or Eurocurrency Rate (as defined in the Credit Agreement) plus 1.75%, (b) the (US) term loan A facility, at our election, Base Rate plus 0.50% or Eurocurrency Rate plus 1.50%, and (c) the Canadian (CAD) term loan A facility, the Australian (AUD) term loan A facility, and the revolving credit facility, an initial rate of, at our election, Base Rate plus 0.75% or Eurocurrency Rate plus 1.75%, and after the end of our fiscal quarter ended June 30, 2018, Base Rate loans plus a margin ranging from 0.25% to 1.00% or Eurocurrency Rate plus a margin from 1.25% to 2.00%, based on the Consolidated Leverage Ratio (as defined in the Credit Agreement); (5) revise covenants including increasing the amounts available under the restricted payment negative covenant and revising the Maximum Consolidated Leverage Ratio (as defined in the Credit Agreement) to include a 4.5 leverage ratio through September 30, 2019 after which the leverage ratio steps down to 4.0.
On November 13, 2018, the Credit Agreement was amended to revise the definition of “Consolidated EBITDA” to increase corporate restructuring allowances and provide for additional flexibility under the covenants for non-core asset dispositions, among other changes.
On January 28, 2020, AECOM entered into Amendment No. 7 to the Credit Agreement which modifies the asset disposition covenant to permit the sale of our Management Services business and the mandatory prepayment provision so that only outstanding term loans are prepaid using the net proceeds from the sale.
Under the Credit Agreement, we are subject to a maximum consolidated leverage ratio and minimum consolidated interest coverage ratio at the end of each fiscal quarter. Our Consolidated Leverage Ratio was 3.6 at December 31, 2019. Our Consolidated Interest Coverage Ratio was 4.9 at December 31, 2019. As of December 31, 2019, we were in compliance with the covenants of the Credit Agreement.
At December 31, 2019 and September 30, 2019, outstanding standby letters of credit totaled $22.8 million and $22.8 million, respectively, under our revolving credit facilities. As of December 31, 2019 and September 30, 2019, we had $1,193.5 million and $1,327.2 million, respectively, available under our revolving credit facility.
2014 Senior Notes
On October 6, 2014, we completed a private placement offering of $800,000,000 aggregate principal amount of the unsecured 5.750% Senior Notes due 2022 (2022 Notes) and $800,000,000 aggregate principal amount of the unsecured 5.875% Senior Notes due 2024 (the 2024 Notes and, together with the 2022 Notes, the 2014 Senior Notes). On November 2, 2015, we completed an exchange offer to exchange the unregistered 2014 Senior Notes for registered notes, as well as all related guarantees. On March 16, 2018, we redeemed all of the 2022 Notes at a redemption price that was 104.313% of the principal amount outstanding plus accrued and unpaid interest. The March 16, 2018 redemption resulted in a $34.5 million prepayment premium, which was included in interest expense.
As of December 31, 2019, the estimated fair value of the 2024 Notes was approximately $886.0 million. The fair value of the 2024 Notes as of December 31, 2019 was derived by taking the mid-point of the trading prices from an observable market input (Level 2) in the secondary bond market and multiplying it by the outstanding balance of the 2024 Notes.
At any time prior to July 15, 2024, we may redeem on one or more occasions all or part of the 2024 Notes at a redemption price equal to the sum of (i) 100% of the principal amount thereof, plus (ii) a “make-whole” premium as of the date of the redemption, plus any accrued and unpaid interest to the date of redemption. In addition, on or after July 15, 2024, the 2024 Notes may be redeemed at a redemption price of 100% of the principal amount thereof, plus accrued and unpaid interest to the date of redemption.
The indenture pursuant to which the 2024 Notes were issued contains customary events of default, including, among other things, payment default, exchange default, failure to provide notices thereunder and provisions related to bankruptcy events. The indenture also contains customary negative covenants.