Notes to Consolidated Financial Statements – (continued)
(Amounts in Millions, Except Per Share Amounts)
For those debt securities that have a premium or discount at the time of issuance, we amortize the amount through interest expense based on the maturity date or the first date the holders may require us to repurchase the debt securities, if applicable. A premium would result in a decrease in interest expense and a discount would result in an increase in interest expense in future periods. We also have recorded debt issuance costs related to certain financing transactions in other assets in our Consolidated Balance Sheets, which are also amortized through interest expense. As of December 31, 2014 and 2013, we had unamortized debt issuance costs of $16.6 and $15.4, respectively.
Our debt securities include covenants that, among other things, limit our liens and the liens of certain of our consolidated subsidiaries, but do not require us to maintain any financial ratios or specified levels of net worth or liquidity.
6.25% Senior Unsecured Notes due 2014
In May 2014, we redeemed all $350.0 in aggregate principal amount of the 6.25% Notes. Total cash paid to redeem the 6.25% Notes was $371.2, which included accrued and unpaid interest of $10.3. In connection with the redemption of the 6.25% Notes, we recognized a loss on early extinguishment of debt of $10.4 which was primarily due to a redemption premium. The loss on early extinguishment of debt was recorded in other expense, net within our Consolidated Statement of Operations.
4.20% Senior Notes due 2024
In April 2014, we issued $500.0 in aggregate principal amount of the 4.20% Senior Notes due 2024 (the "4.20% Notes") at a discount to par. As a result, the 4.20% Notes were reflected on our Consolidated Balance Sheets at a fair value of $499.1 at issuance. The discount of $0.9 and capitalized direct fees, including commissions and offering expenses of $4.4, will be amortized in interest expense through the maturity date of April 15, 2024, using the effective interest method. The net proceeds were $494.7 after deducting discounts, commissions and offering expenses. Interest is payable semi-annually in arrears on April 15th and October 15th of each year, commencing on October 15, 2014. Consistent with our other debt securities, the 4.20% Notes include covenants that, among other things, limit our liens and the liens of certain of our consolidated subsidiaries, but do not require us to maintain any financial ratios or specified levels of net worth or liquidity.
We used the majority of the net proceeds of the 4.20% Notes toward the redemption of our 6.25% Notes as described above.
At any time prior to April 15, 2024, at our option, we may redeem all or some of the 4.20% Notes at the greater of 100% of the principal amount or a "make-whole" amount, plus, in either instance, accrued and unpaid interest to the date of redemption. If we experience a change of control event, combined with a specified downgrade in the credit rating, we must offer to repurchase the 4.20% Notes in cash at a price equal to not less than 101% of the aggregate principal amount of the 4.20% Notes, plus accrued and unpaid interest to the date of repurchase.
10.00% Senior Unsecured Notes due 2017
In July 2013, we redeemed all $600.0 in aggregate principal amount of the 10.00% Senior Unsecured Notes due 2017 (the "10.00% Notes"). Total cash paid to redeem the 10.00% Notes was $630.0. In connection with the redemption of the 10.00% Notes, we recognized a loss on early extinguishment of debt of $45.2, which included a redemption premium of $30.0, the write-off of the remaining unamortized discount of $7.3 and unamortized debt issuance costs of $7.9. The loss on early extinguishment of debt was recorded in other (expense) income, net within our Consolidated Statement of Operations.
4.75% Convertible Senior Notes due 2023
In March 2013, we retired all $200.0 in aggregate principal amount of our 4.75% Convertible Senior Notes due 2023 (the 4.75% Notes"). Of the amount retired, $199.997 in aggregate principal amount of the 4.75% Notes was converted, at the election of the holders, into Interpublic common stock at a conversion rate of 84.3402 shares (actual number) per $1,000 (actual number) principal amount, or approximately 16.9 shares. In connection with the retirement, we exercised our capped call options and elected net share settlement. We received a total of 1.5 settlement shares from the option counterparties as a result of exercising these options.
We maintain a committed corporate credit facility and uncommitted credit facilities with various banks that permit borrowings at variable interest rates. As of December 31, 2014 and 2013, there were no borrowings under our committed corporate credit facility. However, there were borrowings under some of the uncommitted facilities to manage working capital needs. We have guaranteed the repayment of some of these borrowings made by certain subsidiaries. If we lose access to these credit lines, we would have to provide funding directly to some of our international operations. The weighted-average interest rate on outstanding balances under the uncommitted credit facilities as of December 31, 2014 and 2013 was approximately 4.5%.