Andreessen Horowitz recently won a competitive deal to lead the Series A financing of Stir Money, a startup whose software helps video and audio producers, writers and performers manage the income they generate from ads on social media and via direct payments from fans.

The Silicon Valley investment firm valued the young startup, which is led by a former Facebook product designer, at about $100 million, according to two people with knowledge of the deal. The Stir funding and another previously unreported financing of a startup called Karat show how major investors are making bets on software and services for the booming creator economy, made up of tens of millions of individuals who are building businesses from YouTube, social media and apps that help them generate subscription revenue.