Last week, American Express CEO Ken Chenault announced his plans to retire in February 2018. Chenault's retirement will leave just three leading black executives – all of them men – at some of America's largest companies: Ken Frazier of Merck, Roger Ferguson of TIAA and JCPenney’s Marvin Ellison. Chenault has been with AmEx for 37 years, 16 of which he served as CEO.

According to Black Enterprise, President and CEO of the Executive Leadership Council (ELC) Ronald C. Parker describes Chenault's upcoming retirement as bittersweet. However, Parker still praised Chenault's contributions to American Express over the years.

“While we are excited about his success, we are also alarmed and disappointed that we have lost another iconic leader of a Fortune 500 company who is a black CEO,” Parker said to Black Enterprise.

"We are so very proud of the legacy of leadership that Ken has demonstrated over his illustrious career,” Parker said in a press release statement. “He guided the company through the difficult days of 9-11 as the new CEO of American Express, and once again during one of the most challenging global economic recessions of our time. Ken has always been a true model of courageous leadership, operating with the utmost integrity and distinction as demonstrated by his co-chairing and championing the fundraising efforts for the National Museum of African American History and Culture in Washington, D.C., and playing a vital role in the creation of the ELC’s CEO Academy and board diversity initiatives.”

There were seven black CEOs leading Fortune 500 companies in 2007. The number dropped to six in 2013 and then five in 2015, CNN Money reports. By 2016, there were only four black executives of Fortune 500 companies after the departure of Ursula Burns from Xerox.

Black Enterprise goes so far as to say that black executives at large companies are "on the verge of extinction because African Americans are not being identified and groomed for these positions." Parker told the magazine that board of directors at these companies need to be more intentional in identifying talented employees with potential to lead them in the future. He attributed this issue to the lack of diversity in the boardrooms.

"We have to get boards of directors and those who are responsible for succession planning of CEOs much more intentional in identifying talented individuals early on in their executive leadership career trajectory and getting them in position to be considered for the role of chairman and CEO of Fortune 500 companies,” Parker said.

In February, Chenault will be succeeded by Steve Squeri, the current vice chairman of American Express.