Markets work best when everyone has access to the same information. That’s why the U.S. Securities and Exchange Commission requires public companies to file 10-Qs and 10-Ks, and why insider trading rules prohibit trading on the basis of material nonpublic information. Companies are also required (though said requirement is weakly enforced and typically ignored) to report as separate business segments any product line that represents 10% or more of profit or losses, revenue, or assets.

Failure to provide sufficient detail on the operations of today’s gigantic businesses is bad for competition. In the case of big tech companies, it allows them to hide their market power and expand their dominance until it is too late—for either regulators or competitors—to do anything about it.