Well someone lent them money to buy a bankrupt company (Citadel). That's how they got this debt.
Their biggest creditor is driving the ship. There's some reason why they're trying to solve this situation by the end of the year. I don't know what the reason is, but they seem focused on resolving it now.
From industry trades....the problem is Cumulus is barely generating enough cash flow to pay just interest on debt. They missed the November payment and have until Friday to cure the default. Another trigger is Cumulus has been leasing a couple Chicago stations and now have to buy them based on a contracted price of $50 million which would wipe out their cash on hand.
Lew Dickey announced a few months ago he has a $250 million line of credit/investment company which he can leverage into a much higher amount but has never identified what he planned to do with the commitment. The folks lending him the money, reportedly, are also invested in Cumulus. Folks can criticize how he ran the company, etc. but he never missed a payment and actually paid down some of the debt even during the Great Recession.
It is widely suspected in the radio industry Lew will attempt a take back of the company after it goes bankrupt.
As with any company, it's wise to file bankruptcy while you still have enough cash on hand to keep the doors open.
The debt bell will tole for iHeart in 2018 when they have several billion of their $20 billion debt due. Its senior debt, too.
Radio industry leaders believe in the long run, it will be good for radio when both of these companies are shed their immense debt loads.