Substack, the newsletter platform founded in 2017 by CEO Chris Best, has raised $100 million in a Series C funding round led by BOND and The Chernin Group. The round also included participation from Andreessen Horowitz, Klutch Sports Group’s Rich Paul, and Skims co-founder and CEO Jens Grede. This latest investment values Substack at $1.1 billion, up from a $650 million valuation in 2021. The company plans to use the funds to enhance its tools, expand its reach, and provide more support for creators. Substack is shifting its focus from being solely a writer platform to developing a social network that competes with platforms like X for advertising and subscription revenue.