Investors are pushing for more executive compensation disclosure at some companies, and they are taking a novel approach to getting it.

Shareholders have filed a wave of lawsuits, leveraging the Dodd-Frank Act's requirement that they get an advisory vote on executive compensation, to demand even greater disclosures and are threatening to enjoin annual meetings if they don't get it. The lawsuits claim that some companies aren't providing enough compensation information—or that it is inaccurate—for investors to make sound judgments during “say-on-pay” votes.

So far, investors have filed approximately 20 such lawsuits on the grounds that companies are breaching their fiduciary ...