In August, new research found that female CEOs have a 27% chance of facing activist investors while male chief executives’ likelihood is closer to zero. The study’s author provided one possible reason for this phenomenon: the market tends to react negatively when female leadership is announced. That sends a company’s stock price lower, giving it the perception of being undervalued and making it a ripe target for activists.

At Fortune‘s Most Powerful Women Summit on Tuesday, ex-DuPont CEO Ellen Kullman, who confronted activist investor Nelson Peltz in her former role, provided her own perspective. “There are a lot of tough things that women CEOs have been asked to take on, and have taken on and done phenomenally well with. If it makes us a target, that’s part of life,” she said in her first public appearance since leaving DuPont a little over a year ago.

Kullman won an initial proxy fight with Peltz, but when he indicated he would launch another, she stepped down. Her situation was unique—a Fortune 500 CEO facing an activist investor who was pushing for a deal—but the rationale behind her decision to leave is surprisingly relatable: “At some point when you are fighting these fights, you lose your joy a bit. And these jobs are tough. You really need your joy to get up out of bed every morning at 5 am and do what we do,” she said.

She also indicated, quite candidly, that she has no regrets as she took a jab at the pending deal between DuPont and Dow that she’d opposed as CEO. (The companies plan to briefly combine, before breaking apart again.) “Break up, recombine. Break up, recombine,” she said. “That doesn’t create any value except for bankers and lawyers.”