Social media platform Reddit said on Wednesday it had confidentially filed for a proposed initial public offering (IPO) with the U.S. Securities and Exchange Commission.

Reddit, known for its message boards that became the go-to destination for day traders during this year’s meme stock frenzy, was looking at a valuation of more than $15 billion, Reuters had reported in September.

Reddit had roughly 52 million daily active users and over 100,000 communities, or “sub-reddits,” as of October last year.