A new study from Boston Consulting Group adds a new dimension to a growing body of research showing what many have long suspected: Women-run companies have many attributes that make them good investments. Better, perhaps, than male-led companies.

BCG looked at the experiences of 350 companies that had been through the MassChallenge program, which provides support and mentorship for entrepreneurs. Ninety-two of those startups had at least one female founder. 

Not surprisingly, the women raised much less money than the men: an average of $935,000, compared to $2.12 million for all-male executive teams. (Nationally, startup teams with at least one woman co-founder receive only 18 percent of all venture capital dollars).

On average, the women, despite having raised less money, were generating more: $730,000 for the women and $662,000 for the men. Dollar-for-investment-dollar, the differences are even more stark: For every dollar raised, women-run startups generated 78 cents in revenue, compared to 31 cents for men. By that measure, if investors had put the same amount of capital into women-run companies as they did into the ones run by guys, they would have helped generate an additional $85 million in revenue.

Boston Consulting Group is hardly the first, or only, organization to discover that venture capitalists' reluctance to invest in women is likely hurting their returns. A 2015 study by First Round Capital found that among their portfolio of about 300 startups, the teams with a woman co-founder performed 63 percent better--as measured by valuation--than all-male teams.

Research from the Ewing Marion Kauffman Foundation, in 2013, showed that women-led teams have a 35 percent higher return on investment than all-male ones. And, similarly to the BCG study, Kauffman found that when women tech entrepreneurs get venture capital, they generate higher revenues than the guys--in this case, 12 percent higher. A study by Illuminate Ventures also showed that women founders do more with less: Women-led venture-backed companies, in their early stages, had revenues that were comparable to those of men. But they used an average of one-third less capital to get there.

At this point, then, the real surprise isn't that women-led companies are so promising for investors. It's that so few venture capitalists have acknowledged the fact.