Does political spending by corporations benefit their shareholders? A group of investment managers thinks not, and bases this view, in part, on the unprecedented amount of such spending on last year's presidential election.

In fact, they have filed seven shareholder proposals that would ban all political spending from general treasury funds.

"The value of corporate political spending to shareholders is highly questionable, even as the risk it poses to our democracy is self evident. It's time for companies to reverse course and simply exit this activity," says Shelley Alpern, director of social research and advocacy at Clean Yield Asset Management, an RIA based in Norwich, Vt., and one of the investment firms behind the proposals.

Clean Yield filed proposals at EQT Corp., a natural gas company involved in hydraulic fracturing, and 3M. The other investment advisory firms joining the fight are Green Century Capital Management, based in Boston, which filed a proposal at Chevron; Zevin Asset Management, also in Boston, which filed at ExxonMobil; and Harrington Investments, in Napa, Calif., which filed at Starbucks.

Also part of the effort is Responsible Wealth, a network of business leaders, investors and inheritors who represent the richest 5 percent of wealth and/or income in the U.S. and who believe that growing inequality is not in their best interest or the best interest of society. Individual shareholders affiliated with Responsible Wealth filed proposals at Target Corp. and Bank of America.

This proxy season, in fact, political spending ranks as the most popular subject of shareholder proposals. The Proxy Preview 2013 report, released Thursday, found that more than a third of the 365 resolutions filed so far this year ask for more oversight and data on corporate political spending.

Leslie Samuelrich, senior vice president of Green Century Capital Management, said the single largest donation to a Super PAC -- ever -- was in 2012, by Chevron, which gave $2.5 million of company funds.

According to The Center for Public Integrity, "the Supreme Court's Citizens United decision unleashed nearly $1 billion in new political spending in the 2012 election, with media outlets and a small number of political consulting firms raking in the bulk of the proceeds." The 2010 decision allowed unlimited donations to super PACs and nonprofits.

Many other issues will be the focus of shareholder resolutions this proxy season, and they'll get varying amounts of support. But political spending by corporations is one activity that most shareholders want stopped -- at least those not in the executive suite. It's time for corporate leaders to stop raiding the piggy bank to support their interests, and shareholders should tell them so.