You might think such a question would be a no-brainer. But in the supersecret world of private equity, it is anything but. That’s why John Chiang, the treasurer of California, recently called for legislation requiring full transparency in the reporting of fees charged by private equity firms. You might think this issue has little to do with the rest of us. But tens of millions of people have entrusted their retirement to pension funds and other big firms with substantial stakes in private equity investments. Opacity is a byproduct of the secrecy permeating the $3.9 trillion private equity industry. Giants...