An unexpected company is trying to break into the business of telling us how the markets are doing. The Associated Press is launching an index Monday tracking the municipal bond market, the $3.7 trillion world where city and state governments raise money for big projects.

Municipal bonds matter because they make things we use possible, like roads, schools and water systems. And when traders buy and sell those bonds, they’re telling us something.

“By tracking how that municipal bond market is doing, we can kind of get a sense of how investors feel about the health of our governments,” said Lisa Gibbs, AP’s global business editor.

She said the AP Municipal Bond Index will improve the organization’s news coverage of state and local governments. And in a tough business environment for news outlets, the AP, along with its partners at Municipal Bond Information Services, think there’s money to be made selling their bond data to investors.

That may be tricky, as there are already many well-established companies in that space.