The ranks of women at the highest level of U.S. corporate ladder just got thinner.

The resignation of Indra Nooyi after 12 years at the helm of PepsiCo, Inc. (PEP) - Get PepsiCo, Inc. Report means there's one fewer female CEO leading one of companies on the Fortune 500 list.

On Monday, PepsiCo announced that Nooyi, 62, would step down as CEO on Oct. 3, but remain as chairman of the company until 2019. Taking over for Nooyi will be Ramon Laguarta, 54, a 22-year veteran of the corporation who was unanimously elected by the board to succeed Nooyi.

LaGuarta has served since 2017 as president of PepsiCo., overseeing global operations, corporate strategy, public policy and government affairs.

Nooyi's departure will leave 27 women in the top spot of Fortune 500 companies, more than just a few months ago. The total number is down from 2017's record of 32 chief executives.

A trio of recently appointed CEOs include Maggie Timoney of Heineken U.S. (HEINY) , Mary Dillon of Ulta Beauty (ULTA) - Get Ulta Beauty Inc Report , and Michelle Gass of Action Alerts PLUS holding Kohl's (KSS) - Get Kohl's Corporation (KSS) Report .

TheStreet Recommends

Nooyi had led PepsiCo since 2006, and improved shareholder returns by 162% between Dec. 31, 2006 and Dec. 31, 2017. Cash returned to shareholders through dividends and share repurchases totaled $79.4 billion since the beginning of 2006 through the end of 2017.

Nooyi spent a total of 24 years as an executive at PepsiCo, half of her term in the CEO role.

"She has delivered strong and consistent financial performance, managing with an eye toward not only the short-run, but the long-run as well," PepsiCo's Board of Directors presiding director Ian Cook said. "As CEO, she grew revenue more than 80%, outperforming our peers and adding a new billion-dollar brand almost every other year." 

In a statement issued with the announcement, Nooyi referred to some of the recent challenges the company has faced such as consumer tastes shifting towards healthier drinks and snacks, and improving their environmental sustainability. During her tenure, Nooyi improved the corporation's share of revenue from more health conscious 'Good for You' and 'Better for You' product lines from 38% to 50% of total PepsiCo revenue in 2018.

RBC Capital Markets analysts rated PepsiCo. "sector perform" on Monday after news of Nooyi's retirement, setting a price target of $111 for the stock. Analyst Nik Modi indicated that Nooyi's seemingly abrupt departure might be linked to the company's plans to spin off bottling operations to improve operating margins.

Shares of PepsiCo rose 0.9% on Monday after market close.

Jim Cramer: Indra Nooyi's Retirement Is Truly a Tectonic Shift For PepsiCo

How Will Pepsi React to a New CEO?

PepsiCo's Stock Reacts to the CEO Changing of the Guard - Charts Still Bullish