As a former CEO of Merrill Lynch, Smith Barney and Citi Private, Sallie Krawcheck has worked with all kinds of people. But there was still one group she said Wall Street has underserved: female investors.

“It’s not … particularly surprising that industries that are dominated by men tend to do a better job for men,” Krawcheck told CNBC’s “Fast Money” on Tuesday. “And there’s an opportunity for businesses serving women.”

So in 2016, Krawcheck co-founded Ellevest, an investment group focused on serving female investors. This year, the company made CNBC’s 2018 Disruptor 50 list of start-ups that are changing traditional ways of doing business.

“All of those articles … that are about mistakes investors make — over-trading, falling in love with the winners, panicking in downturns, paying too much in fees because of over-trading — really all need to be renamed mistakes that gentlemen investors make,” said Krawcheck, who is CEO.

“The real mistake [women make] is that they tend to under-invest, which is what we’re trying to help them with,” she said.

While the Wall Street veteran said men are welcome at Ellevest — the co-founder and VP of operations are both men — she’s “pretty happy serving half the population that’s been underserved in the investing arena.”

The company, based in New York, helps women understand they have a different set of obstacles in investing, such as longer lifespans, different base salaries than their male counterparts and child-rearing, which can potentially interrupt savings plans.

Ellevest is one of nine companies on this year’s Disruptor 50 list with female CEOs, compared with only three in 2017. Thirteen companies on the list have female founders.

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

SoFi will get crypto investing by 2019, says CEO Anthony Noto

23andMe founder Anne Wojcicki is leading a DNA revolution

Still, the industry standard is much lower. Women-founded companies made up only about 4.4 percent of venture capital deals in 2017, according to PitchBook.

In fact, less than 10 percent of all U.S. fund managers are women, according to a report by Morningstar Research.

“Look to Wall Street. Look closer to home,” Krawcheck said, pointing out that most financial advisors, Wall Street traders, mutual-fund managers and hedge-fund managers are men.