Substack, an online publishing platform, has raised USD 65 million in a Series B funding round led by return investor Andreessen Horowitz (as initially reported by Axios). This round brings total funding to around USD 82.4 million, valuing Substack at approximately USD 650 million.

The funds are to be utilized to rapidly expand the Substack Pro program, where select writers are paid in the first year to help with their newsletter launch, with the company taking 85% of the writers’ subscription revenue. After the first year, the company does not provide a guaranteed payment, but the writers take 90% of their subscription revenue. The company also aims to use the funds to build “increasingly powerful subscription-publishing tools” and “a support infrastructure for independent writers” while investing in community building and supporting local news and reporting.

The Substack Pro program has received controversy recently with criticism surrounding a lack of transparency in whom Substack pays and additional claims that the company is subsidizing anti-trans and right-leaning writers.

Founded in 2017, Substack offers a publishing platform that encompasses design, analytics, and payment infrastructure to assist newsletter subscriptions. The platform enables writers to focus on content creation and monetization via subscriptions. Substack has more than 500,000 paid subscribers as of March 2021.