Boston — IT’S only May, but this presidential election is on track to be one of the most expensive ever. So far two-thirds of political advertising dollars have largely come from anonymous corporate donations, funneled through what have been referred to as “dark money” nonprofit groups that freely engage in electoral and legislative politics, but don’t have to disclose their donors, expenditures or even their members.

One of the most promising strategies to stem the tide of corporate dark money is a proposed rule at the Securities and Exchange Commission that would require public companies to report the amounts and recipients of their political spending. The rule has received a groundswell of support from a bipartisan group of former S.E.C. commissioners, state treasurers and law professors, and has generated more than one million public comments.

Defenders of the status quo argue the companies are simply exercising their right to free speech; critics contend that such speech, when anonymous, does immense harm to the democratic process.

But as lawyers who specialize in investor rights, we see another critical, nonpartisan reason to support the rule: When it comes to political spending, companies are often not as informed as one might think — especially when it comes to dark money.