Chris Sacca, the angel investor in companies like Twitter, Uber and Instagram, gets it. He understands that diversity is simply good for business.

“There is a greed case for diversity,” Sacca told CNN’s Laurie Segall at the Collision Conference yesterday. “Diverse perspectives bring us into markets we didn’t know existed.”

It’s true. There’s a very strong business case for diversity that can affect a company’s bottom line. If you have a gender-diverse company, it can result in a 15 percent greater financial performance compared to a company that is not diverse, according to McKinsey. Meanwhile, ethnic and racial diversity at the leadership and board level leads to a 35 percent greater financial performance. In Silicon Valley specifically, the tech-dominant area could gain $25 billion (a 9% increase) in gross domestic product by 2025.

It’s been common knowledge that diversity is good for business for a while now, but many tech companies can’t seem to get it together. Twitter, for example, is 66% men worldwide and 59% white in the U.S. Twitter also doesn’t have a single black person on its board of directors — something Sacca mentioned — despite the prevalence of black people on Twitter and the power of Black Twitter.

“Twitter is ‘Black Twitter,’” Sacca said on stage. “That is a brand that Black Twitter has given itself. That’s where the hashtags happen … where the excitement is.”

Twitter users are disproportionately people of color, according to Pew Research Center. Of all the people on the Internet, just 23% of them are on Twitter, as of August 2015. Of that 23% of the Internet on Twitter, 28% are black, 28% are Hispanic and 20% are white.

This is not the first time Sacca has spoken about the lack of diversity in tech, and explicitly at Twitter. Back in November, Sacca told DealBook’s Andrew Ross Sorkin that it’s weird that Twitter’s management looks nothing like the people who use the product.

“Look at the user base of Twitter: You have black users over-indexed on Twitter, but you don’t have any representation of that audience in the upper management of the company,” Sacca said in November. “That’s weird.”

Twitter, of course, is not the only tech company failing at diversity. We can’t forget about Apple, Google, Facebook and many others.