The tennis star made this known in an Instagram post on Thursday, five years after establishing her investment portfolio, Serena Ventures.

“In 2014, (yes I know I can keep a secret) I launched Serena Ventures with the mission of giving opportunities to founders across an array of industries. Serena Ventures invests in companies that embrace diverse leadership, individual empowerment, creativity and opportunity.

Through her investment portfolio, Serena Ventures launched in 2014, she has invested in diverse startups worth $12 billion market cap across more than 30 portfolio companies, according to details on the company's website.

Serena Ventures focuses on early-stage companies and has ignited change in startups such as Andela, a software company with offices across Africa and Wave, a remittance platform for Africa, founded by Drew Durbin and Lincoln Quirk, two engineers from Brown University and Harvard University who love and live in Africa.

Andela and Wave were founded in 2014 while the former develop talents in software engineering, the latter serves as a platform for sending money to Africa as easy and affordable as sending a text.

Wave operates in five African nations, including Tanzania and Kenya.

Other investments Serena Williams has invested across the globe include Coinbase, Masterclass, Neighborhood Goods, The Wing, Mayvenn, LittleSpoon, LOLA, Propel, among others.