Silicon Valley's gender gap: Here's where powerful women are moving fast to close it

It took six years, but the CNBC Disruptor 50 list is starting to close the gap. There are more female CEOs and founders and start-up business models and products focused on women than ever before. The 2018 Disruptor list has nine female CEOs, up from just three last year. Thirteen of the companies have at least one female founder. That's still far from closing the gender gap, but the 26 percent of Disruptor companies that have female founders is well ahead of the Silicon Valley average.

Female-founded companies comprised 4.4 percent of all venture capital deals last year, according to PitchBook. Though that sounds grim, it's the largest percentage since 2006. Venture firms, in general, write smaller checks for female founders. Last year the average woman-led VC deal was just over $5 million, compared to a little less than $12 million for a male-led company.

The overall employee base of the companies on this year's list is more diverse than the average of the nearly 1,000 companies that were nominated. None of the 50 companies that made the list have an employee ah base of less than 20 percent female. Fourteen of this year's Disruptor 50 companies reported between 20 percent and 39 percent female employees. Across all the 981 start-ups put forward as Disruptor nominees, 15 percent reported less than 20 percent female employees.

There were some notable outliers in female representation in the Disruptor workplace. More than 70 percent of the employees are female at four of the companies, and it's no surprise, as these four Disruptors are focused on female consumers: Rent the Runway, The RealReal, Ellevest and Thinx.

Ellevest sees a huge untapped market in financial advice for women. Thinx is looking to replace tampons with a new kind of underwear. Progyny is working to revolutionize fertility benefits for women and employers. And Rent the Runway's wardrobe-for-rent options are focused exclusively on women's clothes and accessories, at least for now. While TheRealReal isn't focused just on women's clothes or accessories, the majority of its merchandise is for women, as well as its customer base.

More from CNBC Disruptor 50:
23andMe founder Anne Wojcicki is leading a DNA revolution
SpaceX leading the race to put humans on Mars, and it's led by a woman
Oscar's vision of fairer health care in America

Increasingly, companies view efforts to close the workplace gender gap as not only a social issue and the right thing to do but also critical to business culture and success.

Lack of diversity poses a real financial risk, according to the Disruptor 50 CEOs that responded to our annual survey. The majority of respondents said lack of diversity leads to "Lack of understanding of threats/opportunities due to 'group think.'" The second-biggest risk they cited stemming from lack of diversity is "weakened ability to attract and retain top talent."

Andrew Rubin, CEO and founder of cloud security company Illumio, which reported 20 percent ro 29 percent of its employee based as female, said in the annual Disruptor CEO survey that diversity leads to different perspectives and views on both opportunities and challenges. "Without both of them, we are impeding our long-term success," he said.