Last month, the CEOs of 181 U.S. corporations released a statement committing to a vision of business that is bigger than the single-minded pursuit of profit.

The statement from the U.S. Business Roundtable was signed by the CEOs of Apple, Amazon, Johnson & Johnson, JPMorgan Chase, Walmart and other gigantic multinational corporations.

It says businesses should no longer be run just for the benefit of shareholders but all stakeholders, including customers, employees, suppliers and communities. The signatories commit themselves among other things to compensate employees fairly and provide “important benefits;” deal fairly and ethically with suppliers; and protect the environment by embracing sustainable practices.

The group pitched their statement as a fundamental break with long-held orthodoxy that the purpose of a business is to maximize profits in the interest of creating shareholder value.

Not surprisingly, the initiative was met with more than a little skepticism from such people as Nobel Prize winning economist Joseph Stiglitz, Democratic presidential candidates Elizabeth Warren and Bernie Sanders, and left-leaning activists. They called for concrete action from the CEOs, not just a lofty statement of ideals.

Nevertheless, the statement was a sign that big business is feeling heat on such issues as corporate misconduct, climate change and income inequality. The real pressure isn’t coming from street demonstrations or consumer boycotts, but rather from a quieter and much more powerful source—institutional shareholders.

First, there’s the clout of socially responsible investors. As we outlined in our responsible investing eBook the growth of environmental, social and governance (ESG) investing has been nothing short of phenomenal in recent years. Global assets reached $30.7 trillion in 2018, a 34% increase in just two years, according to a report from the Global Sustainable Investment Alliance.

But it doesn’t stop there. Trillions of dollars are also pouring into passively managed index funds. These assets are concentrated in hands of three giant asset managers—Vanguard, BlackRock and State Street.

Index funds hold every security in an index and, therefore, asset managers don’t have the option of simply selling if they disapprove of a company’s conduct. Instead, they must engage with the company, notably through proxy voting.

And that’s just what the three dominant index fund managers are doing. They each have stewardship policies and publish a stewardship report, where they outline what actions they’ve taken to push companies to improve their performance in the past year.

Elsewhere, trillions more in savings are managed by giant pension fund managers, such as the Caisse de dépôt et placement du Québec and the Canada Pension Plan Investment Board. Here again, these and other large pension fund managers publish stewardship reports and engage with public companies on improving their ESG performance.

In signing the Business Roundtable statement, the CEOs tacitly acknowledged the reality that large blocks of their shares are now in the hands of a small number of fund managers. In the name of their increasing ESG conscious investors, these managers are flexing their muscles to demand companies look beyond profit maximization to a larger definition of what it means to create value.

While we don’t know how far or how fast the Business Roundtable CEOs will move on their commitments, their statement is a clear sign that things are changing. And that’s good news for those of us who want our investment dollars to not only produce decent returns, but also help create a better world.