Colleges and universities collectively owe $240 billion, the Moody’s bond-rating service reports. That debt rose 18 percent, to $145 billion, in the last five years at public universities, Moody’s says. At privates, it went up 3 percent, to $95 billion.

Last year alone, colleges and universities borrowed a record $41.3 billion through municipal bonds, their principal source of debt funding, the financial information firm Thomson Reuters reports. That’s up from $28.7 billion a decade ago.

The annual cost of servicing this accumulated debt more than doubled, from $21 billion in 2003 to $48 billion in 2012, the most recent year for which it has been calculated by researchers at the University of California, Berkeley.

This means 9 percent of college and university budgets, on average, now goes to servicing debt, a cost that has been rising faster than enrollments.

Just the interest payments come to the equivalent of $750 per student per year at public universities, the Berkeley researchers found, and $1,289 at private colleges.

It’s reasonable to assume that this is driving increases in tuition, experts say.

“When you spend more on X, you have to bring in more money from Y, and that Y is usually student tuition,” said Aman Banerji, the program manager at the Roosevelt Institute, which among other things studies what it calls the financialization of higher education.

At Hawaii Pacific, for example, federal data show that since 2013-14 tuition and fees paid by the shrinking number of students have increased more than twice as fast as the national average. (The university’s chief financial officer, Bruce Edwards, said in a written statement that its enrollment and financial challenges are “a familiar trend” in higher education, its borrowing was “to ensure that HPU becomes an even stronger university,” and enrollment is beginning to rebound.)

One reason for this borrowing is that money is comparatively cheap while interest rates remain low.

But much of it is happening because—despite budget cuts at public universities, sluggish endowment growth at private ones, and falling enrollments everywhere—colleges and universities have continued to build new facilities at record-setting rates.

Colleges and universities collectively spent $8.4 billion on new construction and renovations from January through August of this year, up nearly 10 percent over the same period the year before, according to Dodge Data & Analytics, a private company that tracks this. That’s after laying out about $12 billion in each of the last three years.

But the idea that these expenditures will pay for themselves by attracting new students may be wishful thinking, observers caution.

“Sometimes that doesn’t pan out—the ‘if you build it, they will come’ approach,” said Susan Menditto, the director of accounting policy at the National Association of College and University Business Officers.