Companies are now living with a level of scrutiny that most of them couldn’t have imagined at the decade’s start. Heightened regulatory supervision in the wake of so many high-profile corporate scandals is one aspect of this newly intensified attention, which goes way beyond efforts to determine whether companies are merely complying with regulations. The momentum for change is gathering pace; more and more, corporate leaders are living in a goldfish bowl.

Today, 50 countries have their own corporate-governance codes. There may be no legal requirement to abide by them, but many are founded on the principle of "comply or explain": a company that doesn’t comply must explain itself, offering rich pickings for a watchful media.

The attentive gaze of the governance-rating services, which aim to assess the governance practices of the companies they follow, adds to the goldfish bowl effect. Their activities, as some observers see it, amount to no more than superficial box-checking that will have little clout with investors. But the fact that debt-rating agencies such as Standard & Poor’s are developing these services suggests that the opinions of at least some of them will become authoritative.

And then there are the shareholder activists, whose concerns...