The article explores how private companies in the U.S. use different types of debt to finance their operations. They found that firms vary in how much debt they take on and the specific types of debt they use. The researchers discovered that a company's characteristics influence its debt choices, supporting contract theory. Factors that can't be easily seen, like industry trends, also play a big role in determining a company's debt levels. Interestingly, the overall economic conditions don't seem to affect how much debt private firms take on, but they do impact how diverse a company's debt structure is.