In its Fortune 500 C-Suite Snapshot report, executive search firm Spencer Stuart found that women and executives from historically underrepresented groups combined now comprise 49% of C-suite roles in the largest U.S. companies.

But that figure drops to 16% when considering people from underrepresented groups alone. And companies are also not hiring or promoting women into all C-suite jobs in equal measure. For example, women now hold a significant share of Fortune 500 senior leadership roles as CHROs (70%), chief communication officers (64%), and chief inclusion and diversity officer jobs (76%). But they hold few of the higher-paying and more prestigious titles, including CEO (10%), COO (11%), and CFO (18%).

Although women reached a milestone this year when they came to represent 10% of Fortune 500 CEOs for the first time, women of color leading from the top are still exceedingly rare. They include CEOs Lisa Su of semiconductor maker AMD, Thasunda Brown Duckett of asset manager TIAA, and Toni Townes-Whitley of tech company SAIC.

The share of women and both men and women from underrepresented racial and ethnic groups who hold top-tier C-suite jobs is also low. This cohort represents 44% of Fortune 500 chief inclusion and diversity officers, but just 12% of CEOs, 9% of COOs, and 11% of CFOs.

Compared to last year, leadership gains for women as a whole are higher, though the same isn’t true of executives from minority racial and ethnic groups. While women saw a 2 percentage point increase in representation across the C-suite, people from underrepresented groups saw a 1 percentage point decrease, a drop that would be even more significant if white women were excluded from this category.

Nordia Edwards, a Spencer Stuart consultant who specializes in CEO succession planning, attributes this change to increased hiring of racial and ethnic minorities for senior leadership positions between 2020 and 2022, which has since leveled off. Overall, she says, there’s still greater racial diversity in C-suites compared to 2019.

Strengthening the internal pipeline to the CEO office

The most common jobs that people hold before ascending to the corner office are CFO, COO, divisional president, and various kinds of “leapfrog” positions from a level below the C-suite, according to previous research from Spencer Stuart.

Because CFOs and COOs are typically promoted internally, creating a pipeline of diverse talent for those positions in particular is critical to bring greater diversity to corner officers at the largest US companies, says Edwards. “Hopefully all companies seeing this will realize the importance of the internal pipelining towards those roles,” she adds. Edwards says that companies should ask themselves: “How do we impact those numbers?”

When it comes to lagging racial and ethnic diversity in the upper echelons of power, Frances Frei, a professor of technology and operations management at Harvard University, told Fortune that this is an area where corporate leaders often misidentify the problem and claim they can’t find the candidates they need.

“They think they need a time machine to go back in time and work on pipelines or other myths,” she says. The idea is that diversity can be fixed if women and people of color can be encouraged to enter certain areas of study in high school or university. “That will solve the problem in 20 years,” says Frei.

Instead, she says, there’s a more immediate solution. “What you need to do is go find the best of the people that you don't know.”

Do you have insight to share? Got a tip? Contact Lila MacLellan at lila.maclellan@fortune.com or through secure messaging app Signal at 646-820-9525.