More than 40,000 US companies claim to be mission driven—meaning they count contributing to social and/or environmental progress among their core values. But how do you know when they’re sincere and when they’re simply mouthing platitudes to score marketing points? B Lab, a non-profit started two years ago by a trio of former Stanford roommates, has come up with a rating and certification system that can sort out the true believers from the pretenders. The outfits that pass the test can call themselves B Corporations. (B is for benefit, as in social benefit)

When Andrew Kassoy, Jay Coen Gilbert, and Bart Houlahan started B Lab two years ago after two decades years in the business world, they initially planned to create an investment fund that would be the Berkshire Hathaway of the sustainable business realm. But quickly they discovered that they—and the social investment community—needed a rating system to decide if a company deserves to be called sustainable. So they ended up deciding to create a non-profit organization whose primary goal would be to creating such a system. “Instead of everybody coming in and trying to reinvent the wheel, it makes sense for this data to be shared and benchmarked,” Kassoy told me when we met earlier today.

Two years later, they have the system in place, called the B Ratings System, and have qualified more than 200 companies as B Corporations.

Obviously, they still have a long way to go to sign up the majority of the companies that claim to be mission driven. While the slow but steady sign-up process proceeds, Kassoy and his colleagues are shifting some of their attention to initiatives they thought would come later in the organization’s arc: creating a rating system for social investments based on the B Ratings System and pushing changes in state laws to create a legal foundation for social businesses. The B Lab folks plan on unveiling their rating system project officially at the Clinton Global Initiative conference in New York in the fall.

For you socially progressive billionaires out there, they need $4 to $5 million to get it going. So, pony up!