Many founders will tell you that being an entrepreneur is hard work, but when a woman who was once one of the most powerful people on Wall Street says it’s the toughest job she’s ever had…that puts things in perspective.

Speaking on stage at the Fortune Most Powerful Women Next Gen Summit in Laguna Niguel, Calif. on Wednesday afternoon, banking heavyweight-turned-founder Sallie Krawcheck told the audience: “It’s harder to be an entrepreneur than to run Merrill Lynch. I know because I’ve done both.”

Prior to her current venture, Krawcheck held a number of high-level finance posts, including chairman and CEO of research firm Sanford C. Bernstein, CFO of Citigroup c , and head of Merrill Lynch’s global wealth management division.

While she was fired from the latter two jobs—”I hold this world record of being the only woman fired on the front page of the Wall Street Journal twice,” she joked on stage—she maintains that her role as the CEO and co-founder of women’s digital investment platform Ellevest is the most challenging.

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Krawcheck had a few pieces of advice for those women in the Next Gen audience considering making the leap from corporate life to doing their own thing: “You have to be passionate to get you through it, you have to be willing to work extremely hard…and really get your hands dirty.”

Yet working hard isn’t enough, she cautioned, urging aspiring entrepreneurs to “everywhere and always play in traffic.” According to Krawcheck: “If you are head down, not out there not talking about what you’re doing, not going to a conference like this—if no one knows what you’re doing it doesn’t count.”