Serena Williams, 35
If you’re a sports fan, or even if you’re not, this has been the year of Serena Williams. In addition to setting the new record for number of Open-era grand slam titles (23) and being the highest-paid female athlete ($27 million over the past 12 months from June), the tennis pro has flexed her muscles on and off the clay court (and done it while pregnant to boot). In May, she joined the board of online survey giant SurveyMonkey, a month later she expanded her portfolio by investing in food startup Daily Harvest, and has spoken out forcefully for equal pay for women of color.
40 Under 40