I don't want to get too technical in talking about basis points and all the rest, but let me give you an analogy.
A high-investment-grade, stable company will still have access to capital, but those companies that are not investment grade, or perhaps those ones that are on the edge....
Let me give you an example. If I started up a business--let's say a convenience store--and it was going very well, I might decide that I wanted to expand. If I had to start financing that expansion using my credit card and paying 20% per month, I'm probably not going to invest in that. I'm probably not going to expand.
Of course, that's an extreme example, but smaller companies don't have the same access to capital as some of the larger companies, and they will face a much higher borrowing rate. It may not be 20% per month, but it will be something constraining them.