"We invest in different places. We invest in each other," says Williams, speaking exclusively with Yahoo at the Forbes Power Women's Summit in New York City. "We invest in ideas that men don't look at."

Williams doesn't fault men for that. "That's natural, there's nothing wrong with that," she says. She just sees it as proof that women also need the financial power to decide which founders and business ideas get a chance. "We're built different and we are different. So obviously, we see things differently. And I think that's why it's important to put dollars in women's hands and I'm so bullish about having women invest."

As the founder of her own early-stage venture capital firm, Serena Ventures, Williams is intentional about how she uses her own influence — as an investor, an entrepreneur and increasingly a mentor — to expand who gets the opportunity to build something big. 

And even though Williams is globally known as the undisputed GOAT of women's tennis, she increasingly sees opening doors for women founders and her business ventures as her main purpose in this phase of her life and career. "I just wanted to play a little bit for my daughters to see me," she says, referring to her highly anticipated return to the court in the U.S. Open last week after "evolving away from tennis" in 2022. "My main job is VC. So this is just a fun thing I do on the side every now and then. I don't do it often."

Williams traces her passion for uplifting other women to her mother, Oracene Price. While much of the public story surrounding Serena and Venus Williams's rise has centered on their father, Richard Williams, Williams credits her mom with raising five daughters to believe in their own capabilities.

"She wanted to teach us, more than anything, to believe in ourselves and be very confident. Also to be strong women, not needing anyone to do anything [for us]," says Williams. "We can do anything that we want to. Even if we have to build it ourselves."

Now a mother of two daughters herself, Williams says she is passing along essentially the same blueprint to Olympia, 9, and Adira, 3.

"I definitely want them to believe in themselves, and I want them to love themselves and to always be supportive of each other and other women," she says. "It's literally copy-paste" of her mother's most valuable lessons.

That's also central to the work of Serena Ventures. Williams says her ambition is to create an institution whose impact ultimately eclipses her. "We just want to build something bigger than I could ever be," she says.

But her interest in investing isn't limited to finding the next billion-dollar company.

Through her involvement with Reckitt Catalyst, a global initiative supporting entrepreneurs working to improve access to health, hygiene and nutrition, she has spent time advising founders whose companies address urgent needs in their communities, from expanding access to clean water to postpartum healthcare, which is especially close to Williams's heart. In 2022, Williams drew national attention to the Black maternal health crisis by sharing the story of her own near-death experience after giving birth and how her medical concerns were initially dismissed.

"Those things matter," she says. "Those are super important to women and children. We're raising our new generation."

Some of the companies involved may never become the largest in the world, Williams acknowledges. Their work can nevertheless be transformative. "What drew me to Reckitt is the fact that I can do more than invest," she says. "Sometimes money is great, but giving people time and understanding and help and mentorship is more valuable. Because when they finally do get the money, they know exactly how to be successful."

Her own daughters are already developing an understanding of the many roles Williams occupies, even if some are easier to grasp than others. "They say mommy plays tennis," she says, before adding, "and mommy's always working on her computer."

Tennis is more tangible. They can watch their mom step onto a court and immediately understand what she's trying to accomplish. Investing doesn't come with the same scoreboard. "They don't know what's going on behind my computer screen or when I'm on the phone," says Williams, admitting that she has a lot more to learn herself. "I'm a lifelong student. I'll be learning for the rest of my life"

That willingness to keep learning extends even to the arena she mastered long ago. Williams is figuring out what it looks like to return to tennis on her own terms. For now, she's happy to call it a side gig.