PBCT will offer subordinated debt at 4% interest. During the past several years, management has demonstrated that it is unable to put capital to work. Instead they emptied the company treasury paying an unsustainable dividend to shareholders so they could pay themselves unwarranted salaries and bonuses. If they were unable earn a profit on the free money that was laying around then, how will the make a profit with the cost of capital at 4%? The answer is that they won't. But they don't care, they have big lucrative jobs and you can't touch them.
They borrowed the money so they can continue to do buybacks. They previously had run out of money, so there was no way to prop up the stock. This allows them to continue on their course, which is the only course that they know how to follow.